Re: strange ping and traceroute results

[Michael Tewner]

Heh - You _learn_ that Anycast isn't good for TCP, but LinkedIn proved
differently. Their website uses TCP (obviously), works almost always, and
gracefully recovers when Anycast throws a curve.

There's a great interview on Packet Pushers with LinkedIn Global
Engineering:

Packet Pushers: Show 286: Busting Anycast TCP Myths
http://packetpushers.net/podcast/podcasts/show-286-busting-anycast-tcp-myths/

...and a blog post:
https://engineering.linkedin.com/network-performance/tcp-over-ip-anycast-pipe-dream-or-reality

-Mike Tewner



On Fri, Nov 25, 2016 at 12:14 AM, Amos Shapira 
wrote:

> Anycast is not suitable for TCP.
> It IS fantastic for DNS (which uses UDP), which is the first thing a
> client does most of the time to find the server.
> Akamai control server groups by allocating per-customer per-object host
> names, then these can be resolved using their very highly customised DNS
> servers to the right server (also taking into account dynamic changes like
> server cluster load or failure).
> Since DNS uses UDP and the traffic consists on one packet in each
> direction, Anycast is ideal for that scenario.
> The actual content transfer (e.g. move streams, which is where I with
> Akamai for stan.com.au) doesn't use Anycast.
>
> On 24 November 2016 at 04:06, Shachar Shemesh  wrote:
>
>> On 22/11/16 02:19, Amos Shapira wrote:
>>
>> On 21 November 2016 at 18:20, Shachar Shemesh 
>> wrote:
>>
>>> The DNS resolving google.com guesses your gegraphical location, and
>>> gives you an answer that is nearest where you are. If you use another DNS
>>> to query the domain, you will get a different IP:
>>>
>>
>> It's not always a "guess your geographic location". The smarter ones use
>> Anycast to advertise the same IP address from multiple locations on the
>> Internet and let BGP do its magic to route your packets to the nearest
>> server, taking into account any congestion or other transient connection
>> speed changes. This is how Google's DNS 8.8.8.8 works, or Akamai's CDN. The
>> nice thing about it is that you get optimal response even at the host
>> resolution stage. The DNS server can then take its knowledge of the DNS
>> query source address into account when it decides which IP address to
>> resolve to.
>>
>> It's pretty neat, personally I find it a fascinating trick:
>> https://en.wikipedia.org/wiki/Anycast
>>
>> It is, quite fascinating. It is not, unfortunately, as useful as you make
>> it out to be. Neither Google nor Akamai use it for web traffic, for example.
>>
>> The reason is twofold. First, anycast is poorly equipted to handle TCP
>> connections. There is a (remote) possibility that the handler of your IP
>> would change mid-request, which would not play nice with your connection.
>>
>> The second, more pertinent, reason is that , at least for Akamai, they
>> would like to be able to control which server you reach when you make a
>> request. The would like to be able to re-route your in case something bad
>> happens to that server. DNS TTL can be set as low as 30 or 60 seconds. BGP
>> routes have much longer settle times.
>>
>> Shachar
>>
>
>
>
> --
> 
>
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>
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Re: strange ping and traceroute results

[Amos Shapira]

Anycast is not suitable for TCP.
It IS fantastic for DNS (which uses UDP), which is the first thing a client
does most of the time to find the server.
Akamai control server groups by allocating per-customer per-object host
names, then these can be resolved using their very highly customised DNS
servers to the right server (also taking into account dynamic changes like
server cluster load or failure).
Since DNS uses UDP and the traffic consists on one packet in each
direction, Anycast is ideal for that scenario.
The actual content transfer (e.g. move streams, which is where I with
Akamai for stan.com.au) doesn't use Anycast.

On 24 November 2016 at 04:06, Shachar Shemesh  wrote:

> On 22/11/16 02:19, Amos Shapira wrote:
>
> On 21 November 2016 at 18:20, Shachar Shemesh  wrote:
>
>> The DNS resolving google.com guesses your gegraphical location, and
>> gives you an answer that is nearest where you are. If you use another DNS
>> to query the domain, you will get a different IP:
>>
>
> It's not always a "guess your geographic location". The smarter ones use
> Anycast to advertise the same IP address from multiple locations on the
> Internet and let BGP do its magic to route your packets to the nearest
> server, taking into account any congestion or other transient connection
> speed changes. This is how Google's DNS 8.8.8.8 works, or Akamai's CDN. The
> nice thing about it is that you get optimal response even at the host
> resolution stage. The DNS server can then take its knowledge of the DNS
> query source address into account when it decides which IP address to
> resolve to.
>
> It's pretty neat, personally I find it a fascinating trick:
> https://en.wikipedia.org/wiki/Anycast
>
> It is, quite fascinating. It is not, unfortunately, as useful as you make
> it out to be. Neither Google nor Akamai use it for web traffic, for example.
>
> The reason is twofold. First, anycast is poorly equipted to handle TCP
> connections. There is a (remote) possibility that the handler of your IP
> would change mid-request, which would not play nice with your connection.
>
> The second, more pertinent, reason is that , at least for Akamai, they
> would like to be able to control which server you reach when you make a
> request. The would like to be able to re-route your in case something bad
> happens to that server. DNS TTL can be set as low as 30 or 60 seconds. BGP
> routes have much longer settle times.
>
> Shachar
>



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Re: strange ping and traceroute results

[Shachar Shemesh]

On 22/11/16 02:19, Amos Shapira wrote:
> On 21 November 2016 at 18:20, Shachar Shemesh  > wrote:
>
> The DNS resolving google.com  guesses your
> gegraphical location, and gives you an answer that is nearest
> where you are. If you use another DNS to query the domain, you
> will get a different IP:
>
>
> It's not always a "guess your geographic location". The smarter ones
> use Anycast to advertise the same IP address from multiple locations
> on the Internet and let BGP do its magic to route your packets to the
> nearest server, taking into account any congestion or other transient
> connection speed changes. This is how Google's DNS 8.8.8.8 works, or
> Akamai's CDN. The nice thing about it is that you get optimal response
> even at the host resolution stage. The DNS server can then take its
> knowledge of the DNS query source address into account when it decides
> which IP address to resolve to.
>
> It's pretty neat, personally I find it a fascinating trick:
> https://en.wikipedia.org/wiki/Anycast
>
It is, quite fascinating. It is not, unfortunately, as useful as you
make it out to be. Neither Google nor Akamai use it for web traffic, for
example.

The reason is twofold. First, anycast is poorly equipted to handle TCP
connections. There is a (remote) possibility that the handler of your IP
would change mid-request, which would not play nice with your connection.

The second, more pertinent, reason is that , at least for Akamai, they
would like to be able to control which server you reach when you make a
request. The would like to be able to re-route your in case something
bad happens to that server. DNS TTL can be set as low as 30 or 60
seconds. BGP routes have much longer settle times.

Shachar
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Re: strange ping and traceroute results

[Amos Shapira]

On 21 November 2016 at 18:20, Shachar Shemesh  wrote:

> The DNS resolving google.com guesses your gegraphical location, and gives
> you an answer that is nearest where you are. If you use another DNS to
> query the domain, you will get a different IP:
>

It's not always a "guess your geographic location". The smarter ones use
Anycast to advertise the same IP address from multiple locations on the
Internet and let BGP do its magic to route your packets to the nearest
server, taking into account any congestion or other transient connection
speed changes. This is how Google's DNS 8.8.8.8 works, or Akamai's CDN. The
nice thing about it is that you get optimal response even at the host
resolution stage. The DNS server can then take its knowledge of the DNS
query source address into account when it decides which IP address to
resolve to.

It's pretty neat, personally I find it a fascinating trick:
https://en.wikipedia.org/wiki/Anycast

--Amos
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Re: strange ping and traceroute results

[Shachar Shemesh]

On 20/11/16 07:01, Shlomo Solomon wrote:
> When I try ping or traceroute to www.google.com, I get strange results.
> Both utilities "think" that www.google.com is at 213.57.*.*, but those
> addresses belong to my Internet provider - Hotnet.
>
> What am I missing?
>
> [solomon@shlomo1]$ ping www.google.com
> PING www.google.com (213.57.23.29) 56(84) bytes of data.
> 64 bytes from 213.57.23.29: icmp_seq=1 ttl=59 time=17.1 ms
> 64 bytes from 213.57.23.29: icmp_seq=2 ttl=59 time=16.8 ms
> 64 bytes from 213.57.23.29: icmp_seq=3 ttl=59 time=17.1 ms
>
> [solomon@shlomo1]$ sudo traceroute www.google.com
> traceroute to www.google.com (213.57.24.55), 30 hops max, 60 byte packets 
> 1  router-1.solomon (10.0.0.138)  1.010 ms  1.007 ms  1.006 ms
> 2  core-213-57-3-7.ptr.hotnet.net.il (213.57.3.7)  15.379 ms  15.741 ms  
> 16.551 ms 
> 3  ae7.101.hfa.mx-lns.con.hotnet.net.il (213.57.3.221) 36.177 ms  36.182 ms  
> 36.178 ms 
> 4  core-213-57-3-217.ptr.hotnet.net.il (213.57.3.217)  17.736 ms  17.736 ms  
> 17.733 ms 
The DNS resolving google.com guesses your gegraphical location, and
gives you an answer that is nearest where you are. If you use another
DNS to query the domain, you will get a different IP:


216.58.218.196 from
http://mxtoolbox.com/SuperTool.aspx?action=a%3awww.google.com=toolpage
74.125.22.103 from https://www.ultratools.com/tools/dnsLookupResult
216.58.209.68 from http://ping.eu/nslookup/

If you are dead set on using a different IP than your local one, you can
use this trick to do this.

Shachar
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Re: strange ping and traceroute results

[Shlomo Solomon]

On Sun, 20 Nov 2016 10:18:37 +0200
shimi  wrote:

Thanks for your very detailed reply. As you correctly assumed, I did
learn about traceroute before re-inventing the wheel, so most of what
you wrote was familiar. But I didn't know about the -I parameter.
 
traceroute -I www.google.com does, as you wrote, get to the target. 

Since I think that that's more than I'm expected to emulate, I
added a more "friendly" error message to my program in the case of a
(FW caused) timeout.




-- 
Shlomo Solomon
http://the-solomons.net
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Re: strange ping and traceroute results

[Amos Shapira]

Google.com is not one computer. Google spreads their locations all over the
world including pops in many ISP's.

https://peering.google.com/#/

On 20 November 2016 at 19:18, shimi  wrote:

>
>
> On Sun, Nov 20, 2016 at 9:38 AM, Shlomo Solomon 
> wrote:
>
>> On Sun, 20 Nov 2016 08:25:18 +0200
>> shimi  wrote:
>>
>> > I believe it's called a CDN and/or local compute clusters and the
>> > purpose of it is to give you a better user experience, which is a
>> > Good Thing (TM).
>> >
>> snip ... snip ... snip
>> >
>> > Why do you think it's a problem and are trying to avoid it?
>> >
>>
>> Thanks. I agree that this is "normally" a Good Thing (TM). So I guess I
>> have to explain my problem. For a course I'm doing, I had to write
>> traceroute in Python   -   re-invent the wheel :-)
>>
>> My program works, but I noticed it never reaches www.google.com so I
>> checked the "real" traceroute and found the same behaviour.
>>
>> It seems that neither my program nor the real traceroute handle this
>> properly - i.e. they never report that they've reached the final hop.
>> I've included traceroute www.godaddy.com and traceroute www.google.com
>> for comparison. You can see that traceroute www.google.com never
>> reaches the address it's trying to reach - 213.57.24.49
>>
>>
> I do not believe the fact that you "can't reach it" has anything to do
> with www.google.com resolving to an IP in Israel.
>
> Since I am assuming that for your re-inventing the wheel exercise, you did
> learn and understood what traceroute does; But let me explain it anyway for
> the answer to your question lies within...
>
> What traceroute does is essentially send packets to the destination IP by
> certain protocol. Popular choices include UDP (I believe that's what the
> Linux one does by default), ICMP (I believe that's what the Windows one
> does by default) and TCP.
>
> However, it doesn't send the packet as one normally would, with a large
> TTL (Time To Live) value which is expected to reach anywhere on the
> Internet (typical values: >= 64), rather than it starts of with setting a
> minimal value for TTL, for the purpose of _not_ getting into the target IP,
> rather than the packet being dropped by the very first router (hop) on the
> chain, resulting in error in packet  delivery.
>
> Per the IP specification, such a packet discarding SHOULD produce an ICMP 
> (Internet
> Control Message Protocol) message being sent by the hop that has discarded
> the packet towards the originator of the original packet, telling it that
> "TTL expired in transit". The original idea was to avoid packets travelling
> to infinitum in routing loops - by decreasing the TTL by 1 on every hop the
> packet passes, eventually it will zero out, and the packet will be
> discarded, not causing a bandwidth storm.
>
> So, I said SHOULD. Does it always? Well, no. Some hosts on the Internet
> employ something called "a firewall", which blocks ICMP for various reasons
> (you'll hear the word "security" in some places); As a regular user who
> opens his browser and types in 'https://www.google.com/' - you don't
> really care. ICMP is not typically used when establishing a connection to a
> server on the Internet (well, that's not accurate; lack of PMTU discovery
> is an excellent way to get your IT people to pull some hairs out when any
> tunnel is involved, including dialup and Israeli "MPLS" connections, a.k.a.
> "dialer-less HOT"... but for the sake of discussion and to explain how did
> they ended up deciding to filter those packets and affect you - probably
> not knowing what else they break - then "it's not typically used")
>
> Sometimes the filtering is not of ICMP at all, rather than the original
> protocol you're trying to probe with; A random UDP port at the area of
> 30,000 typically has no business traversing their network, so your original
> packet (if you're using UDP packets for your traceroute program) may have
> been firewalled and never reached a router to lower its TTL by 1 and expire
> it in transit to produce the ICMP message you're expecting... In that case,
> where ICMP is not actually block, rather your UDP connection is, you might
> find out that running:
>
> traceroute -I 213.57.24.49
>
> (I for ICMP Echo based traceroute)
>
> Does actually get you to the target. However, you'll have to run this as
> root, because generating ICMP packets is not something the regular user can
> do. Of course, you can opt to chmod +s your traceroute binary...
>
> Hope this helps,
>
> -- Shimi
>
>
>
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Re: strange ping and traceroute results

[shimi]

On Sun, Nov 20, 2016 at 9:38 AM, Shlomo Solomon 
wrote:

> On Sun, 20 Nov 2016 08:25:18 +0200
> shimi  wrote:
>
> > I believe it's called a CDN and/or local compute clusters and the
> > purpose of it is to give you a better user experience, which is a
> > Good Thing (TM).
> >
> snip ... snip ... snip
> >
> > Why do you think it's a problem and are trying to avoid it?
> >
>
> Thanks. I agree that this is "normally" a Good Thing (TM). So I guess I
> have to explain my problem. For a course I'm doing, I had to write
> traceroute in Python   -   re-invent the wheel :-)
>
> My program works, but I noticed it never reaches www.google.com so I
> checked the "real" traceroute and found the same behaviour.
>
> It seems that neither my program nor the real traceroute handle this
> properly - i.e. they never report that they've reached the final hop.
> I've included traceroute www.godaddy.com and traceroute www.google.com
> for comparison. You can see that traceroute www.google.com never
> reaches the address it's trying to reach - 213.57.24.49
>
>
I do not believe the fact that you "can't reach it" has anything to do with
www.google.com resolving to an IP in Israel.

Since I am assuming that for your re-inventing the wheel exercise, you did
learn and understood what traceroute does; But let me explain it anyway for
the answer to your question lies within...

What traceroute does is essentially send packets to the destination IP by
certain protocol. Popular choices include UDP (I believe that's what the
Linux one does by default), ICMP (I believe that's what the Windows one
does by default) and TCP.

However, it doesn't send the packet as one normally would, with a large TTL
(Time To Live) value which is expected to reach anywhere on the Internet
(typical values: >= 64), rather than it starts of with setting a minimal
value for TTL, for the purpose of _not_ getting into the target IP, rather
than the packet being dropped by the very first router (hop) on the chain,
resulting in error in packet  delivery.

Per the IP specification, such a packet discarding SHOULD produce an
ICMP (Internet
Control Message Protocol) message being sent by the hop that has discarded
the packet towards the originator of the original packet, telling it that
"TTL expired in transit". The original idea was to avoid packets travelling
to infinitum in routing loops - by decreasing the TTL by 1 on every hop the
packet passes, eventually it will zero out, and the packet will be
discarded, not causing a bandwidth storm.

So, I said SHOULD. Does it always? Well, no. Some hosts on the Internet
employ something called "a firewall", which blocks ICMP for various reasons
(you'll hear the word "security" in some places); As a regular user who
opens his browser and types in 'https://www.google.com/' - you don't really
care. ICMP is not typically used when establishing a connection to a server
on the Internet (well, that's not accurate; lack of PMTU discovery is an
excellent way to get your IT people to pull some hairs out when any tunnel
is involved, including dialup and Israeli "MPLS" connections, a.k.a.
"dialer-less HOT"... but for the sake of discussion and to explain how did
they ended up deciding to filter those packets and affect you - probably
not knowing what else they break - then "it's not typically used")

Sometimes the filtering is not of ICMP at all, rather than the original
protocol you're trying to probe with; A random UDP port at the area of
30,000 typically has no business traversing their network, so your original
packet (if you're using UDP packets for your traceroute program) may have
been firewalled and never reached a router to lower its TTL by 1 and expire
it in transit to produce the ICMP message you're expecting... In that case,
where ICMP is not actually block, rather your UDP connection is, you might
find out that running:

traceroute -I 213.57.24.49

(I for ICMP Echo based traceroute)

Does actually get you to the target. However, you'll have to run this as
root, because generating ICMP packets is not something the regular user can
do. Of course, you can opt to chmod +s your traceroute binary...

Hope this helps,

-- Shimi
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Re: strange ping and traceroute results

[Shlomo Solomon]

On Sun, 20 Nov 2016 08:25:18 +0200
shimi  wrote:

> I believe it's called a CDN and/or local compute clusters and the
> purpose of it is to give you a better user experience, which is a
> Good Thing (TM).
> 
snip ... snip ... snip
> 
> Why do you think it's a problem and are trying to avoid it?
> 

Thanks. I agree that this is "normally" a Good Thing (TM). So I guess I
have to explain my problem. For a course I'm doing, I had to write
traceroute in Python   -   re-invent the wheel :-) 

My program works, but I noticed it never reaches www.google.com so I
checked the "real" traceroute and found the same behaviour. 

It seems that neither my program nor the real traceroute handle this
properly - i.e. they never report that they've reached the final hop.
I've included traceroute www.godaddy.com and traceroute www.google.com
for comparison. You can see that traceroute www.google.com never
reaches the address it's trying to reach - 213.57.24.49




[solomon@shlomo1 ~]$ sudo traceroute www.godaddy.com
traceroute to www.godaddy.com (23.44.253.116), 30 hops max, 60 byte
packets 
1  router-1.solomon (10.0.0.138)  0.610 ms  0.979 ms  0.977 ms
2  core-213-57-3-7.ptr.hotnet.net.il (213.57.3.7)  15.370 ms  15.753
ms  16.148 ms 
3  ae7.101.hfa.mx-lns.con.hotnet.net.il (213.57.3.221) 16.544 ms
16.543 ms  16.553 ms 
4  core-213-57-3-217.ptr.hotnet.net.il (213.57.3.217)  17.345 ms
18.132 ms  18.524 ms 
5  207.232.21.146 (207.232.21.146)  20.941 ms  20.948 ms  20.944 ms 
6 core1-TenGigE0-4-0-1.hfa.nv.net.il (212.143.8.226)  21.311 ms
core1-0-5-0-21-edge1.hfa.nv.net.il (212.143.7.173)  22.651 ms  22.379 ms 
7  cdn-sw1-1-35-core1-2-5-hfa.hfa.nv.net.il (212.143.7.252)  21.129 ms
cdn-sw1-1-45-core1.hfa.nv.net.il (212.143.7.209)  18.333 ms 
cdn-sw1-1-43-core1.hfa.nv.net.il (212.143.7.201)  19.097 ms 
8 a23-44-253-116.deploy.static.akamaitechnologies.com (23.44.253.116)
18.299 ms  18.290 ms  18.703 ms



[solomon@shlomo1 ~]$ sudo traceroute www.google.com
traceroute to www.google.com (213.57.24.49), 30 hops max, 60 byte
packets 
1 router-1.solomon (10.0.0.138)  0.943 ms  0.937 ms  0.934 ms 
2 core-213-57-3-7.ptr.hotnet.net.il (213.57.3.7)  15.313 ms  15.720 ms
16.114 ms 
3  ae7.101.hfa.mx-lns.con.hotnet.net.il (213.57.3.221) 16.128 ms
16.526 ms  16.526 ms 
4  core-213-57-3-217.ptr.hotnet.net.il (213.57.3.217)  21.311 ms
21.692 ms  21.675 ms 
5  * * * 
6  * * * 
7  * * * 
8  * * * 
9  * * *
10  * * *
11  * * *
12  * * *
13  * * *
14  * * *
15  * * *
16  * * *
17  * * *
18  * * *
19  * * *
20  * * *
21  * * *
22  * * *
23  * * *
24  * * *
25  * * *
26  * * *
27  * * *
28  * * *
29  * * *
30  * * *
[solomon@shlomo1 ~]$ 



-- 
Shlomo Solomon
http://the-solomons.net
Sent by Claws Mail 3.11.1 - KDE 4.14.5 - LINUX Mageia 5


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Re: strange ping and traceroute results

[shimi]

On 20 Nov 2016 07:02, "Shlomo Solomon" <shlomo.solo...@gmail.com> wrote:
>
> When I try ping or traceroute to www.google.com, I get strange results.
> Both utilities "think" that www.google.com is at 213.57.*.*, but those
> addresses belong to my Internet provider - Hotnet.
>
> What am I missing?
>
> [solomon@shlomo1]$ ping www.google.com
> PING www.google.com (213.57.23.29) 56(84) bytes of data.
> 64 bytes from 213.57.23.29: icmp_seq=1 ttl=59 time=17.1 ms
> 64 bytes from 213.57.23.29: icmp_seq=2 ttl=59 time=16.8 ms
> 64 bytes from 213.57.23.29: icmp_seq=3 ttl=59 time=17.1 ms
>
> [solomon@shlomo1]$ sudo traceroute www.google.com
> traceroute to www.google.com (213.57.24.55), 30 hops max, 60 byte packets
> 1  router-1.solomon (10.0.0.138)  1.010 ms  1.007 ms  1.006 ms
> 2  core-213-57-3-7.ptr.hotnet.net.il (213.57.3.7)  15.379 ms  15.741 ms
16.551 ms
> 3  ae7.101.hfa.mx-lns.con.hotnet.net.il (213.57.3.221) 36.177 ms  36.182
ms  36.178 ms
> 4  core-213-57-3-217.ptr.hotnet.net.il (213.57.3.217)  17.736 ms  17.736
ms  17.733 ms
> 5  * * *
> 6  * * *
> 7  * * *
> 8  * * *

I believe it's called a CDN and/or local compute clusters and the purpose
of it is to give you a better user experience, which is a Good Thing (TM).

There are other similar POPs I saw at least in BezeqInt.

The question really is:

Why do you think it's a problem and are trying to avoid it?

If your reply includes the letters M-I-T-M, please consider that without
installing a fake CA cert on your host, MITMing an SSL/TLS connection WILL
cause a connection set up error from your browser.

HTH,

-- Shimi
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Re: strange ping and traceroute results

[Shlomo Solomon]

Thanks. Any way to get around this? 
I just tried pinging Google-UK (www.google.co.uk) and Google-Canada
(www.google.ca) and I see the same behaviour.



On Sun, 20 Nov 2016 05:13:29 +
Geoffrey Mendelson <geoffreymendel...@gmail.com> wrote:

> Google.com resolves to addresses routed to Google.co.il and 8.8.4.4
> and 8.8.8.8 are routed to a local nameserver.
> 
> It is all part of a local cache system.
> 
> Geoff.
> 
> On Sun, Nov 20, 2016, 07:02 Shlomo Solomon <shlomo.solo...@gmail.com>
> wrote:
> 
> > When I try ping or traceroute to www.google.com, I get strange
> > results. Both utilities "think" that www.google.com is at
> > 213.57.*.*, but those addresses belong to my Internet provider -
> > Hotnet.
> >
> > What am I missing?
> >
> > [solomon@shlomo1]$ ping www.google.com
> > PING www.google.com (213.57.23.29) 56(84) bytes of data.
> > 64 bytes from 213.57.23.29: icmp_seq=1 ttl=59 time=17.1 ms
> > 64 bytes from 213.57.23.29: icmp_seq=2 ttl=59 time=16.8 ms
> > 64 bytes from 213.57.23.29: icmp_seq=3 ttl=59 time=17.1 ms
> >
> > [solomon@shlomo1]$ sudo traceroute www.google.com
> > traceroute to www.google.com (213.57.24.55), 30 hops max, 60 byte
> > packets 1  router-1.solomon (10.0.0.138)  1.010 ms  1.007 ms  1.006
> > ms 2  core-213-57-3-7.ptr.hotnet.net.il (213.57.3.7)  15.379 ms
> > 15.741 ms 16.551 ms
> > 3  ae7.101.hfa.mx-lns.con.hotnet.net.il (213.57.3.221) 36.177 ms
> > 36.182 ms  36.178 ms
> > 4  core-213-57-3-217.ptr.hotnet.net.il (213.57.3.217)  17.736 ms
> > 17.736 ms  17.733 ms
> > 5  * * *
> > 6  * * *
> > 7  * * *
> > 8  * * *
> >
> >
> > --
> > Shlomo Solomon
> > http://the-solomons.net
> > Sent by Claws Mail 3.11.1 - KDE 4.14.5 - LINUX Mageia 5
> >
> >
> > ___
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> > Linux-il@cs.huji.ac.il
> > http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
> >



-- 
Shlomo Solomon
http://the-solomons.net
Sent by Claws Mail 3.11.1 - KDE 4.14.5 - LINUX Mageia 5


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Re: strange ping and traceroute results

[Shlomo Solomon]

This seems to be specific to www.google.com. Other addresses work as
expected.

Trailing dot does not change anything.

On Sun, 20 Nov 2016 05:15:04 +
Daniel Shahaf <d...@daniel.shahaf.name> wrote:

> Shlomo Solomon wrote on Sun, Nov 20, 2016 at 07:01:10 +0200:
> > When I try ping or traceroute to www.google.com, I get strange
> > results. Both utilities "think" that www.google.com is at
> > 213.57.*.*, but those addresses belong to my Internet provider -
> > Hotnet.
> > 
> > What am I missing?
> > 
> 
> Try with a trailing dot?
> 
> % ping www.google.com.
> 
> 
> Try other domains?
> 
> % ping www.$(pwgen).com



-- 
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http://the-solomons.net
Sent by Claws Mail 3.11.1 - KDE 4.14.5 - LINUX Mageia 5


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Re: strange ping and traceroute results

[Daniel Shahaf]

Shlomo Solomon wrote on Sun, Nov 20, 2016 at 07:01:10 +0200:
> When I try ping or traceroute to www.google.com, I get strange results.
> Both utilities "think" that www.google.com is at 213.57.*.*, but those
> addresses belong to my Internet provider - Hotnet.
> 
> What am I missing?
> 

Try with a trailing dot?

% ping www.google.com.


Try other domains?

% ping www.$(pwgen).com

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strange ping and traceroute results

[Shlomo Solomon]

When I try ping or traceroute to www.google.com, I get strange results.
Both utilities "think" that www.google.com is at 213.57.*.*, but those
addresses belong to my Internet provider - Hotnet.

What am I missing?

[solomon@shlomo1]$ ping www.google.com
PING www.google.com (213.57.23.29) 56(84) bytes of data.
64 bytes from 213.57.23.29: icmp_seq=1 ttl=59 time=17.1 ms
64 bytes from 213.57.23.29: icmp_seq=2 ttl=59 time=16.8 ms
64 bytes from 213.57.23.29: icmp_seq=3 ttl=59 time=17.1 ms

[solomon@shlomo1]$ sudo traceroute www.google.com
traceroute to www.google.com (213.57.24.55), 30 hops max, 60 byte packets 
1  router-1.solomon (10.0.0.138)  1.010 ms  1.007 ms  1.006 ms
2  core-213-57-3-7.ptr.hotnet.net.il (213.57.3.7)  15.379 ms  15.741 ms  16.551 
ms 
3  ae7.101.hfa.mx-lns.con.hotnet.net.il (213.57.3.221) 36.177 ms  36.182 ms  
36.178 ms 
4  core-213-57-3-217.ptr.hotnet.net.il (213.57.3.217)  17.736 ms  17.736 ms  
17.733 ms 
5  * * *
6  * * *
7  * * *
8  * * *


-- 
Shlomo Solomon
http://the-solomons.net
Sent by Claws Mail 3.11.1 - KDE 4.14.5 - LINUX Mageia 5


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Ping status with SIGQUIT

[Amos Shapira]

Something I just found and thought it might be good to share:
http://blog.sqawasmi.com/index.php/2009/09/28/ping-tip-ctl-backslash/

Sending SIGQUIT (ctrl-\) to ping will make it print a status line and
continue pinging.

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ping problems

[Erez D]

hi

i have an openwrt (linux) router, with regular firewall rules (nat,
related+established,clamp-mss-to-pmtu, etc).

if i ping from the router to the internet, it works ok
however if i ping from inside my lan to the internet, the first 30-70 pings
works, then it stops working (i.e. 100% packet lost after the first 30-70)
using tcpdump inside my router shows the icmps going through the wan
interface but none come back.

any idea ?
erez.
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Re: ping problems

[Aviv Greenberg]

If you ping another destination during the hang - does it work?
If you ifdown and ifup the interfaces (wan + lan) on the router after
a hang - is it released?
an icmp packet is short so i don't think this is the case but: what is
the MTU on the lan/wan?

Also, use a tool like mtr
http://en.wikipedia.org/wiki/Mtr_(My_traceroute) to detect any packet
loss along the route.

2009/5/27 Erez D erez0...@gmail.com:
 hi

 i have an openwrt (linux) router, with regular firewall rules (nat,
 related+established,clamp-mss-to-pmtu, etc).

 if i ping from the router to the internet, it works ok
 however if i ping from inside my lan to the internet, the first 30-70 pings
 works, then it stops working (i.e. 100% packet lost after the first 30-70)
 using tcpdump inside my router shows the icmps going through the wan
 interface but none come back.

 any idea ?
 erez.

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-- 

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http://www.brainyquote.com/quotes/authors/f/frank_lloyd_wright.html

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Re: ping problems

[Erez D]

On Wed, May 27, 2009 at 9:41 AM, Aviv Greenberg avivg...@gmail.com wrote:

 If you ping another destination during the hang - does it work?

a download i started before the ping continues even after the ping is dead


 If you ifdown and ifup the interfaces (wan + lan) on the router after
 a hang - is it released?
 an icmp packet is short so i don't think this is the case but: what is
 the MTU on the lan/wan?

as you said, the ping packets are smaller then the mtu (and all are same
size)
also ping is connectionless, so it makes sense if the lost packets are
spread randomly
but not if in the beginning all pass and in the end all fail



 Also, use a tool like mtr
 http://en.wikipedia.org/wiki/Mtr_(My_traceroute)http://en.wikipedia.org/wiki/Mtr_%28My_traceroute%29to
  detect any packet
 loss along the route.

mtr works from both router and lan
there is some packet lost on the closer servers, but none at the target
but it is the same for both router and lan.

thanks,
erez.



 2009/5/27 Erez D erez0...@gmail.com:
  hi
 
  i have an openwrt (linux) router, with regular firewall rules (nat,
  related+established,clamp-mss-to-pmtu, etc).
 
  if i ping from the router to the internet, it works ok
  however if i ping from inside my lan to the internet, the first 30-70
 pings
  works, then it stops working (i.e. 100% packet lost after the first
 30-70)
  using tcpdump inside my router shows the icmps going through the wan
  interface but none come back.
 
  any idea ?
  erez.
 
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 --

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 http://www.brainyquote.com/quotes/authors/f/frank_lloyd_wright.html

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Re: ping problems

[Aviv Greenberg]

Try netstat -s to checks for errors/drops on the WAN interface.
Anything interesting?

If a ping from the router always succeeds, and after some time fails
from the lan AND during failure you see the packets go from the lan
out to the wan but doesn't come back at all - it sounds like something
is wrong with the outgoing ping request packet.

Did you see any difference between a goog ping and bad ping packets?

On Wed, May 27, 2009 at 10:05, Erez D erez0...@gmail.com wrote:


 On Wed, May 27, 2009 at 9:41 AM, Aviv Greenberg avivg...@gmail.com wrote:

 If you ping another destination during the hang - does it work?

 a download i started before the ping continues even after the ping is dead

 If you ifdown and ifup the interfaces (wan + lan) on the router after
 a hang - is it released?
 an icmp packet is short so i don't think this is the case but: what is
 the MTU on the lan/wan?

 as you said, the ping packets are smaller then the mtu (and all are same
 size)
 also ping is connectionless, so it makes sense if the lost packets are
 spread randomly
 but not if in the beginning all pass and in the end all fail


 Also, use a tool like mtr
 http://en.wikipedia.org/wiki/Mtr_(My_traceroute) to detect any packet
 loss along the route.

 mtr works from both router and lan
 there is some packet lost on the closer servers, but none at the target
 but it is the same for both router and lan.

 thanks,
 erez.


 2009/5/27 Erez D erez0...@gmail.com:
  hi
 
  i have an openwrt (linux) router, with regular firewall rules (nat,
  related+established,clamp-mss-to-pmtu, etc).
 
  if i ping from the router to the internet, it works ok
  however if i ping from inside my lan to the internet, the first 30-70
  pings
  works, then it stops working (i.e. 100% packet lost after the first
  30-70)
  using tcpdump inside my router shows the icmps going through the wan
  interface but none come back.
 
  any idea ?
  erez.
 
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 --

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 http://www.brainyquote.com/quotes/authors/f/frank_lloyd_wright.html





-- 

Mitch Hedberg  - My fake plants died because I did not pretend to
water them. - http://www.brainyquote.com/quotes/authors/m/mitch_hedberg.html

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Firefox -remote ping() gone, here's a workaround

[Yosef Meller]

--Boundary_(ID_4J4w7ohUWxWs9BJUbxzr4A)
Content-type: text/plain; charset=us-ascii; format=flowed
Content-transfer-encoding: 7BIT

Hi, all

There used to be a way of determining if firefox is running by checking 
the return value of:

$ firefox -remote ping()

However I tried it on 1.0 PR and it's gone. I googled for it and found a 
message that says the same thing so I guess it's not my problem. Anyway, 
I needed that, so I wrote a workaround that uses ps. The attached script 
is designed to open a page in firefox, but if firefox is already 
running, do it in a new tab.

I submit this for your enjoyment and critical review. I wonder if there 
is a better (or simply other) way to do it.

-- 
   No, I do not contain myself,
   were the final words from the set of self-excluding sets. :-)

--Boundary_(ID_4J4w7ohUWxWs9BJUbxzr4A)
Content-type: text/plain; name=catchthefox.sh
Content-transfer-encoding: 7BIT
Content-disposition: inline; filename=catchthefox.sh

#! /bin/bash

# catchthefox.sh
# By Yosef Meller
# License: GPL
#
# A script to launch a page in a new tab if firefox is running, 
# Otherwise run firefox and open the page.

FIREFOX=/usr/bin/firefox
HOST=localhost

# Different distros have different executable name, so grep -i
# For example, in Mandrake it's MozillaFirefox, in Gentoo it's just firefox.
ps -A | grep -i firefox  /dev/null

if [ $? -eq 0 ]
then
$FIREFOX -remote openURL(http://$HOST/lib/library.cgi,new-tab) 
else
$FIREFOX http://$HOST/lib/library.cgi 
fi


--Boundary_(ID_4J4w7ohUWxWs9BJUbxzr4A)--

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Re: Firefox -remote ping() gone, here's a workaround

[Oleg Goldshmidt]

Yosef Meller [EMAIL PROTECTED] writes:

 ps -A | grep -i firefox  /dev/null

I think you are in danger here: your grep is a separate process and it
*may* appear in the process table and be grepped (since the command
line contains what you are looking for) even when firefox is not
run. There is no lock that says grep does not start until ps finishes
reading the process table.

One useful trick is egrep -i [f]irefox, another is grep -v grep.

RedHat have /usr/bin/pgrep and /usr/bin/pkill utilities, and I have used

pname () 
{ 
/bin/ps auxww | /bin/egrep $@ | /bin/grep -v egrep
}

pnum () 
{ 
pname $@ | /bin/awk '{print $2}'
}

pkill () 
{ 
kill -9 `pnum [EMAIL PROTECTED]
}

in my .bashrc since before RedHat introduced theirs.

Another, related point: your script is only good for a single-user
machine. Since ps -A lists *all* processes then your grep may find
someone else's firefox. You will be better off parsing the long output
of ps and finding your own firefox. E.g. RedHat's pgrep will allow
that.

Finally, it should be relatively easy to make your script work for any
browser that supports a variant of -remote option. You may pass the
browser and the option on the command line, or via the environment,
with firefox and -remote as default values.

-- 
Oleg Goldshmidt | [EMAIL PROTECTED]

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Re: Firefox -remote ping() gone, here's a workaround

[Yosef Meller]

Oleg Goldshmidt wrote:
Yosef Meller [EMAIL PROTECTED] writes:
ps -A | grep -i firefox  /dev/null
I think you are in danger here: your grep is a separate process and it
*may* appear in the process table and be grepped (since the command
line contains what you are looking for) even when firefox is not
run. There is no lock that says grep does not start until ps finishes
reading the process table.
ps -A does not show command line arguments, so we're safe here. But see 
below...

One useful trick is egrep -i [f]irefox, another is grep -v grep.
RedHat have /usr/bin/pgrep and /usr/bin/pkill utilities, and I have used
pname () 
{ 
/bin/ps auxww | /bin/egrep $@ | /bin/grep -v egrep
}

pnum () 
{ 
pname $@ | /bin/awk '{print $2}'
}

pkill () 
{ 
kill -9 `pnum [EMAIL PROTECTED]
}

in my .bashrc since before RedHat introduced theirs.
Another, related point: your script is only good for a single-user
machine. Since ps -A lists *all* processes then your grep may find
someone else's firefox. You will be better off parsing the long output
of ps and finding your own firefox. E.g. RedHat's pgrep will allow
that.
OK, let's use:
ps auxc | grep $USER | grep $FIREFOX
The 'c' displays the true executable name without command line args, 
achieving much the same effect of ps -A, and I think this is a bit more 
elegant.

Finally, it should be relatively easy to make your script work for any
browser that supports a variant of -remote option. You may pass the
browser and the option on the command line, or via the environment,
with firefox and -remote as default values.
I guess you're right, but I don't know any other browser that suports that.
--
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  were the final words from the set of self-excluding sets. :-)
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Re: Firefox -remote ping() gone, here's a workaround

[Oleg Goldshmidt]

Yosef Meller [EMAIL PROTECTED] writes:

 ps -A does not show command line arguments

Oh, I didn't realize this. Is it specified anywhere? I guess the
explanation for the -f option may be read to infer that. In any case,
I missed it.

  Finally, it should be relatively easy to make your script work for any
  browser that supports a variant of -remote option. You may pass the
  browser and the option on the command line, or via the environment,
  with firefox and -remote as default values.
 
 I guess you're right, but I don't know any other browser that suports that.

Netscape and mozilla are the obvious ones, kfmclient exists for
konqueror, and I am fairly confident that you could use w3 via
emacsclient/gnuclient (though I have never tried it), and you never
know what else lurks out there...

-- 
Oleg Goldshmidt | [EMAIL PROTECTED]

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Re: Firefox -remote ping() gone, here's a workaround

[Lior Kaplan]

I don't see why do you workaround the problem before you make sure 
there's a bug report? I searched Mozilla's bugzilla and nothing is 
reported about ping() not working.

I'm sure letting the Mozilla people find why it doesn't work is shorter 
than working around the problem. Please report that as a bug. Let me 
know if you have questions.

My intent is not to lecture you, but make sure the maximum number of 
people will enjoy the solution.

https://bugzilla.mozilla.org
Yosef Meller wrote:
--Boundary_(ID_4J4w7ohUWxWs9BJUbxzr4A)
Content-type: text/plain; charset=us-ascii; format=flowed
Content-transfer-encoding: 7BIT
Hi, all
There used to be a way of determining if firefox is running by checking 
the return value of:

$ firefox -remote ping()
However I tried it on 1.0 PR and it's gone. I googled for it and found a 
message that says the same thing so I guess it's not my problem. Anyway, 
I needed that, so I wrote a workaround that uses ps. The attached script 
is designed to open a page in firefox, but if firefox is already 
running, do it in a new tab.

I submit this for your enjoyment and critical review. I wonder if there 
is a better (or simply other) way to do it.

--
Regards,
Lior Kaplan
[EMAIL PROTECTED]
http://www.Guides.co.il
Debian GNU/Linux unstable (SID)
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can ping myself, but not others

[Boris Gorelik]

Hello,
I've installed Mandrake10.0 on a computer in my lab (the computer has two 
network cards. At the network configuration stage I've filled in all the 
required parameters: IP (static), DNS, gateway, hostname. The eth0 interface 
started with no error message, but the network is not accessible. I can ping 
myself, but pinging anything else (including the gateway and the dns servers) 
fails with Host unreachable error (using both IP and hostname). Before 
installing mdk10.0, there was redhat linux installed on this computer and the 
network worked fine.
 There are two identical onboard network cards (Intel) network cards, but the 
first one is recognized as Gigabit one. 

ifconfig does not say RUNNING:

[bgbg]$ sudo /sbin/ifconfig
eth0 Link encap:Ethernet HWaddr XX:XX:XX:XX:XX:X
inet addr:XXX.XX.XXX.248 Bcast:XXX.XXX.XXX.255 Mask:255.255.255.0
inet6 addr: ::XXX:::/XX Scope:Link
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 Mb) TX bytes:0 (0.0 b)
Base address:0x8000 Memory: e030-e032

lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
RX packets:845 errors:0 dropped:0 overruns:0 frame:0
TX packets:845 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:64422 (62.9 Kb) TX bytes:64422 (62.9 Kb)

Any ideas?
-- 
Boris Gorelik
Thu, 05/Aug/2004, 18 Av 5764

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Re: can ping myself, but not others

[Omer Zak]

Check routing of the packets?
What does traceroute say?
Boris Gorelik wrote:
Hello,
I've installed Mandrake10.0 on a computer in my lab (the computer has two 
network cards. At the network configuration stage I've filled in all the 
required parameters: IP (static), DNS, gateway, hostname. The eth0 interface 
started with no error message, but the network is not accessible. I can ping 
myself, but pinging anything else (including the gateway and the dns servers) 
fails with Host unreachable error (using both IP and hostname). Before 
installing mdk10.0, there was redhat linux installed on this computer and the 
network worked fine.
 There are two identical onboard network cards (Intel) network cards, but the 
first one is recognized as Gigabit one. 

ifconfig does not say RUNNING:
[bgbg]$ sudo /sbin/ifconfig
eth0 Link encap:Ethernet HWaddr XX:XX:XX:XX:XX:X
inet addr:XXX.XX.XXX.248 Bcast:XXX.XXX.XXX.255 Mask:255.255.255.0
inet6 addr: ::XXX:::/XX Scope:Link
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 Mb) TX bytes:0 (0.0 b)
Base address:0x8000 Memory: e030-e032
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
RX packets:845 errors:0 dropped:0 overruns:0 frame:0
TX packets:845 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:64422 (62.9 Kb) TX bytes:64422 (62.9 Kb)
Any ideas?
 --- Omer
My own blog is at http://www.livejournal.com/users/tddpirate/
My opinions, as expressed in this E-mail message, are mine alone.
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Re: can ping myself, but not others

[Oleg Goldshmidt]

Boris Gorelik [EMAIL PROTECTED] writes:

 Hello,
 I've installed Mandrake10.0 on a computer in my lab (the computer has two 
 network cards. At the network configuration stage I've filled in all the 
 required parameters: IP (static), DNS, gateway, hostname. The eth0 interface 
 started with no error message, but the network is not accessible. I can ping 
 myself, but pinging anything else (including the gateway and the dns servers) 
 fails with Host unreachable error (using both IP and hostname). Before 
 installing mdk10.0, there was redhat linux installed on this computer and the 
 network worked fine.

Sanity check: make sure your network cable is not crossed (assuming
you connect via a switch or hub). There is no firewall anywhere on the
route, is there?

-- 
Oleg Goldshmidt | [EMAIL PROTECTED]

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Re: Running ping, need help

[Shachar Shemesh]

Oron Peled wrote:
About disturbing other alarm/ualarms, you may want to look at Stevens
[advanced programming in the Unix environment, circa 1995] which has
a very nice chapter about implementing sleep(3) using alarm(2) with all
the common pittfalls (saving timers while setting them, avoiding critical
races in that stage, etc.)
 

Anyone can send me an excert from this book? I don't have it.
 Shachar
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Re: Running ping, need help

[Muli Ben-Yehuda]

On Fri, Jun 11, 2004 at 10:58:54AM +0300, Shachar Shemesh wrote:
 Oron Peled wrote:
 
 About disturbing other alarm/ualarms, you may want to look at Stevens
 [advanced programming in the Unix environment, circa 1995] which has
 a very nice chapter about implementing sleep(3) using alarm(2) with all
 the common pittfalls (saving timers while setting them, avoiding critical
 races in that stage, etc.)

 Anyone can send me an excert from this book? I don't have it.

You should run, not walk, to your nearest book seller and buy
it. It's the bible of UNIX system programming. 

[you're welcome to borrow my well-thumbed copy, but I'll need it
back]. 

Cheers, 
Muli 
-- 
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Re: Running ping, need help

[Gilad Ben-Yossef]

On Wednesday 09 June 2004 18:52, Shachar Shemesh wrote:
 Hi all,

 I'm trying to provide a library call that will run a ping to a server.
 The catch is that it needs to be done as a non-root user, and I would
 like to avoid any solution that involves any SUID or root running
 processes beyond what is already there. That leaves me, pretty much,
 ping.

Actually, not quite. You don't need to be root, you need your process to have 
the CAP_NET_RAW capability. This is not quite one and the same. You can start 
root and drop all privileges except the needed CAP_NET_RAW or even better - 
you can have a wrapper that starts as root, drops all unneeded caps and then 
execs the original program.

See:
http://www.securityfocus.com/infocus/1400

and also:
http://www.linuxjournal.com/article.php?sid=5737

Hope this helps,
Gilad



-- 
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http://www.codefidence.com


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Re: Running ping, need help

[Gilad Ben-Yossef]

On Thursday 10 June 2004 10:12, Gilad Ben-Yossef wrote:
 On Wednesday 09 June 2004 18:52, Shachar Shemesh wrote:
  Hi all,
 
  I'm trying to provide a library call that will run a ping to a server.
  The catch is that it needs to be done as a non-root user, and I would
  like to avoid any solution that involves any SUID or root running
  processes beyond what is already there. That leaves me, pretty much,
  ping.

 Actually, not quite. You don't need to be root, you need your process to
 have the CAP_NET_RAW capability. This is not quite one and the same. You
 can start root and drop all privileges except the needed CAP_NET_RAW or
 even better - you can have a wrapper that starts as root, drops all
 unneeded caps and then execs the original program.


I thought of it, and actually if you already start as root and loose 
previliges, you can just as well open an ICMP socket and leave it open and 
just use this for all ICMP requests later. More secure and simpler.

Cheers,
Gilad

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Re: Running ping, need help

[Oron Peled]

On Wednesday 09 June 2004 23:48, Shachar Shemesh wrote:
 RTFM pselect, and more specifically, select_tut, for an answer to that 
 one.

I am fully aware for pselect importance in the general case, but I was 
refering to your specific example in which it was used only to wait for
the event to happen (or was I wrong and I/O was also involved?).

In that case, simply waiting for either signal to happen (it's a one-shot
signal) without blocking the other should be ok.

[BTW, I first leant from your remark about the select_tut manpage...nice].

 I'm not sure I see how sigprocmask enters into the picture. 

My flop, I was talking about sigsuspend (to wait for either SIGCHLD
or SIGALRM) and wrote sigprocmask :-(

 Still, I think this is a jackpot. Suggested pseudo code:
 sigprocmask disabling SIGCHILD and SIGALRM
 ask for ualarm for wakeup
 fork (child starts ping, with or without cancelling ualarm first)
 sigsupend on the above two signals
 check which one, send INT to ping if alrm
 waitpid
 return mask to usual, cancel alarm, etc.

Good. (s/sigprocmask/sigsuspend/ in my original paragraph and you'll
see we meant the same thing).

After sending the old reply I found another problem: man ualarm shows
nothing -- does my memory misslead me? I thought it was (almost-)stanard
[i.e: very common in Unices including Linux]

About disturbing other alarm/ualarms, you may want to look at Stevens
[advanced programming in the Unix environment, circa 1995] which has
a very nice chapter about implementing sleep(3) using alarm(2) with all
the common pittfalls (saving timers while setting them, avoiding critical
races in that stage, etc.)

-- 
Oron Peled Voice/Fax: +972-4-8228492
[EMAIL PROTECTED]  http://www.actcom.co.il/~oron

Linux lasts longer!
-- Kim J. Brand [EMAIL PROTECTED]


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Running ping, need help

[Shachar Shemesh]

Hi all,
I'm trying to provide a library call that will run a ping to a server. 
The catch is that it needs to be done as a non-root user, and I would 
like to avoid any solution that involves any SUID or root running 
processes beyond what is already there. That leaves me, pretty much, ping.

The catch is that I get a timeout value, and I'm asked to abort if the 
operation is not complete within that time (and report status).
The code I'm using is doing the following (pseudo code warning):
block sigchld
fork
(child - execve ping -c 1 -n -q hostname)
pselect for timeout or sigchld
kill INT the ping
waitpid to get status.

Now here's the thing. Sometimes, I can see that the ping returned fairly 
immediately, but the full timeout was spent. I suspect that, due to the 
fact pselect is not a system call in Linux, ping has indeed finished 
before the pselect, and the signal got lost. Does anyone have any 
alternative solutions to implement what I'm doing here?

   Shachar
--
Shachar Shemesh
Lingnu Open Source Consulting ltd.
http://www.lingnu.com/
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Re: Running ping, need help

[Maxim Kovgan]

On Wed, 9 Jun 2004, Shachar Shemesh wrote:

 Hi all,

 I'm trying to provide a library call that will run a ping to a server.
 The catch is that it needs to be done as a non-root user, and I would
 like to avoid any solution that involves any SUID or root running
 processes beyond what is already there. That leaves me, pretty much, ping.

 The catch is that I get a timeout value, and I'm asked to abort if the
 operation is not complete within that time (and report status).
 The code I'm using is doing the following (pseudo code warning):
 block sigchld
 fork
 (child - execve ping -c 1 -n -q hostname)
 pselect for timeout or sigchld
 kill INT the ping
 waitpid to get status.

man pthread_create
man pthread_mutex_init

good luck.
M.


 Now here's the thing. Sometimes, I can see that the ping returned fairly
 immediately, but the full timeout was spent. I suspect that, due to the
 fact pselect is not a system call in Linux, ping has indeed finished
 before the pselect, and the signal got lost. Does anyone have any
 alternative solutions to implement what I'm doing here?

   Shachar

 --
 Shachar Shemesh
 Lingnu Open Source Consulting ltd.
 http://www.lingnu.com/


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 Max Kovgan..
 email: maxk _at_ cs.technion.ac.il .
 phone: 972-4-8294528   .



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Re: Running ping, need help

[Ehud Karni]

-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1

On Wed, 09 Jun 2004 18:52:16 +0300, Shachar Shemesh [EMAIL PROTECTED] wrote:

 I'm trying to provide a library call that will run a ping to a server.
 The catch is that it needs to be done as a non-root user, and I would
 like to avoid any solution that involves any SUID or root running
 processes beyond what is already there. That leaves me, pretty much, ping.

 The catch is that I get a timeout value, and I'm asked to abort if the
 operation is not complete within that time (and report status).
 The code I'm using is doing the following (pseudo code warning):
 block sigchld
 fork
 (child - execve ping -c 1 -n -q hostname)
 pselect for timeout or sigchld
 kill INT the ping
 waitpid to get status.

 Now here's the thing. Sometimes, I can see that the ping returned fairly
 immediately, but the full timeout was spent. I suspect that, due to the
 fact pselect is not a system call in Linux, ping has indeed finished
 before the pselect, and the signal got lost. Does anyone have any
 alternative solutions to implement what I'm doing here?

Caution: untested suggestion.

You can use alarm(2) in the child process before `exec'ing the ping.
Then it either will finish normally (exit 0) or will fail for any
reason (including SIGALRM).

In this way, you can use blocking `waitpid' in the parent process.

If you try my suggestion, please report here.

Ehud.


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Re: Running ping, need help

[Shachar Shemesh]

Maxim Kovgan wrote:
man pthread_create
man pthread_mutex_init
good luck.
M.
 

I'm afraid you will have to be WAY more specific than this. Why would 
threads and mutexes help me at all?

 Shachar
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Re: Running ping, need help

[Shachar Shemesh]

Ehud Karni wrote:
Caution: untested suggestion.
You can use alarm(2) in the child process before `exec'ing the ping.
Then it either will finish normally (exit 0) or will fail for any
reason (including SIGALRM).
 

No good
In this way, you can use blocking `waitpid' in the parent process.
If you try my suggestion, please report here.
 

First, I can't send a SIGALRM to ping - it ignores it. That's not a real 
problem. I can send it to the parent process, and then do a signal 
handler that translates ALRM on the parent to INT on the child, and do a 
waitpid as suggested.

The more serious problem is that ALRM has a resolution of seconds, 
which is not good enough. Obviously, I can simulate the same behavior 
with a THIRD process. The following schema:
parent does waitpid on child 1 only
child 1 does execve ping
child 2 does select for timeout, and then sends SIGINT to child 1.

When parent's waitpid returns, it sends SIGKILL to child 2.
While I think this will work, it's too twisted to contemplate at this 
time of the day. If nothing better comes along by tomorrow, I'll have a 
look at this. Can anyone spot a race here? Also, are there any unwanted 
implications to using SIGKILL in non-emergency situations? I would 
rather not use SIGTERM or SIGINT, as each of these processes carries 
around the entire Wine environment. I would like to avoid using threads, 
for the same reason. Too much factors, not enough certainty.

Ehud.
 

On second thought, I can get rid of the SIGKILL by having that process 
call exit after the select+kill, and just send it SIGALRM from the 
parent before doing waitpid on it.

 Shachar
--
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Lingnu Open Source Consulting ltd.
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Re: Running ping, need help

[Ehud Karni]

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Hash: SHA1

On Wed, 09 Jun 2004 19:31:31 +0300, Shachar Shemesh [EMAIL PROTECTED] wrote:

 The more serious problem is that ALRM has a resolution of seconds,
 which is not good enough.

You can use `setitimer(2)' instead. It has microseconds resolution,
but IIRC it really works on the PC tics (~ 55 ms).

Ehud.


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Re: Running ping, need help

[Muli Ben-Yehuda]

On Wed, Jun 09, 2004 at 06:52:16PM +0300, Shachar Shemesh wrote:

 Now here's the thing. Sometimes, I can see that the ping returned fairly 
 immediately, but the full timeout was spent. I suspect that, due to the 
 fact pselect is not a system call in Linux, ping has indeed finished 
 before the pselect, and the signal got lost. Does anyone have any 
 alternative solutions to implement what I'm doing here?

how about replacing the signal with e.g. a pipe? i.e. fork twice, have
the first son share a pipe with the father, then fork  exec the ping,
and wait on it. Once the ping returns, write to the pipe. In the
father, select on the pipe with the timeout you want. No async events
(signals), no race... 

Cheers, 
Muli 
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http://www.mulix.org | http://mulix.livejournal.com/



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Re: Running ping, need help

[Oron Peled]

On Wednesday 09 June 2004 19:18, Shachar Shemesh wrote:
 Maxim Kovgan wrote:
 man pthread_create
 man pthread_mutex_init
 Why would threads and mutexes help me at all?

They won't, wrong direction. Instead, why blocking SIGCHLD
and getting to possible critical races? An simpler alternative
seems to set up signal handlers for SIGALRM and SIGCHLD
(before forking), then fire alarm(2) (or ualarm(2)) and simply
sigprocmask(2) for one of them to happen?

-- 
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[EMAIL PROTECTED]  http://www.actcom.co.il/~oron

Can you sum up plan 9 in layman's terms?
It does everything Unix does only less reliably - kt


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Re: Running ping, need help

[Shachar Shemesh]

Muli Ben-Yehuda wrote:
how about replacing the signal with e.g. a pipe? i.e. fork twice, have
the first son share a pipe with the father, then fork  exec the ping,
and wait on it. Once the ping returns, write to the pipe. In the
father, select on the pipe with the timeout you want. No async events
(signals), no race... 

Cheers, 
Muli 
 

True, but if I'm going to have three processes, I have already suggested 
a solution that is pipeless. Then again, I think we have a jackpot here 
after all, but it goes to Ehud and Oron.

Shachar
--
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Re: Running ping, need help

[Shachar Shemesh]

Oron Peled wrote:
On Wednesday 09 June 2004 19:18, Shachar Shemesh wrote:
 

Maxim Kovgan wrote:
   

man pthread_create
man pthread_mutex_init
 

Why would threads and mutexes help me at all?
   

They won't, wrong direction. Instead, why blocking SIGCHLD
and getting to possible critical races?
RTFM pselect, and more specifically, select_tut, for an answer to that 
one. The short answer is because it's the cleanest solution, assuming 
you have a kernel implemented pselect. Unfortunetly, Linux doesn't, 
hence the trouble we're seeing.

An simpler alternative
seems to set up signal handlers for SIGALRM and SIGCHLD
(before forking), then fire alarm(2) (or ualarm(2)) and simply
sigprocmask(2) for one of them to happen?
 

I'm not sure I see how sigprocmask enters into the picture. Are you 
saying to cancel one as soon as the other happens? That sounds pretty 
certain to fail.

Still, I think this is a jackpot. Suggested pseudo code:
sigprocmask disabling SIGCHILD and SIGALRM
ask for ualarm for wakeup
fork (child starts ping, with or without cancelling ualarm first)
sigsupend on the above two signals
check which one, send INT to ping if alrm
waitpid
return mask to usual, cancel alarm, etc.
Does anyone see a fault in this setup, aside from the possibility that 
whoever called me may have had other plans for ualarm?

 Shachar
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Re: ping....

[Boaz Rymland]

Hmm... maybe related, maybe not: on tuesday, IIRC, my postfix 
configuration, which utilize anti UCE checks through 
proxies.relays.monkeys.com started rejecting mails from _anywhere_. As I 
saw no information about this in the media (although I searched) and 
since I don't have much time to debug this, the only solution I've found 
is to disable this RBL check.
Maybe this scenario worked for you too?

BTW, anyone else seen this ? I saw no headlines like monkeys RBL server 
blacklisted the world... as it was with that other service not so long 
ago.

BR.

Diego Iastrubni wrote:

Last message I got was from Yesterday before it was Monday 15:04:14.

Is this list dead or having problems?
(cc when replying)
 

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ping....

[Diego Iastrubni]

Last message I got was from Yesterday before it was Monday 15:04:14.

Is this list dead or having problems?
(cc when replying)

-- 

diego,

Please avoid sending me Word or PowerPoint attachments.
See http://www.fsf.org/philosophy/no-word-attachments.html



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Re: ping....

[Shlomi Fish]

On Wednesday 17 March 2004 19:24, Diego Iastrubni wrote:
 Last message I got was from Yesterday before it was Monday 15:04:14.

 Is this list dead or having problems?
 (cc when replying)

Hi Diego!

It seems you have problems in receiving mail from this list. I received many 
other messages. You can see the messages that were received since in the 
archives.

Regards,

Shlomi Fish
-- 

-
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Homepage:http://shlomif.il.eu.org/

Quidquid latine dictum sit, altum viditur.
[Whatever is said in Latin sounds profound.]

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Re: ping....

[Shachar Shemesh]

Diego Iastrubni wrote:

sorry... i remember when this list had about 10-20 mails per day... 

we about less then 30 the last week... 
 

I think this is just a slow month. People are aborad or similar.

Knowing this list, it's enough for one or two people to be abroad to 
lessen the load, assuming these are the right people.

Looking at the archives 
(http://mirror.hamakor.org.il/archives/linux-il/), you can see that last 
month had pretty much the volumes you are talking about.

 Shachar

--
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Open Source integration consultant
Home page  resume - http://www.shemesh.biz/


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Re: [Fwd: Re: ping....+ database project question]

[Omer Zak]

On Sun, 19 Oct 2003, Maxim K. wrote:

 Abstract:
 the db will contain information about real estates (flats/houses etc.)
 i thought in OOD terms, and came to:
 address, person, estate- data  objects or - tables.using these
 terms, there will be relations between these tables.

 i understand there's solution of simply putting it all into 1 huge
 table.and search by simple or/and matches. what i don't unserstand is:
 how do i decide how much to go down with the most basic tables, vs. one
 huge table.
 as someone pointed this out to be the normalization question.

 Q1: where do i read about it ?

At home I have a book about practical issues of database design.  I don't
remember the author name, but the book explains about normalization,
about mistaken notions about relational databases in general, etc.

 Q2: which platform shall i use for the GUI frontend of this DB, given
 that i chose the DBMS to be PostgreSQL.
 i have written in: C, C++, Java
 (i see C isn't much of a help in GUI...except maybeGTK frontend)
 i think i also can handle Python.
 which tools are there ? what you suggest ?
 need Hebrew support, of course .. so if GUI supports - good for it.

You may want to design your system as a 3-part system:
- Database backend
- Web site (running on your own PC): server, CGI scripts and Web pages
- The GUI will be provided by your browser (Mozilla, if you have the
  freedom to choose a platform).

BiDi/Hebrew support is good out of the box.

If you prefer to do without Web server, you can develop your application
as a Mozilla chrome, and then you'll have database backend and browser
frontend.  Refer to the O'Reilly book Developing applications with
Mozilla.
 --- Omer
My opinions, as expressed in this E-mail message, are mine alone.
They do not represent the official policy of any organization with which
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Re: ping....

[Idan Sofer]

On Saturday 18 October 2003 23:27, Diego Iastrubni wrote:
 sorry... i remember when this list had about 10-20 mails per day...

 we about less then 30 the last week...
Trolls to the rescue!:-D


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[Fwd: Re: ping....+ database project question]

[Maxim K.]

sorry... i remember when this list had about 10-20 mails per day... 

we about less then 30 the last week... 
pre-semestral silence ... the silence before the storm :)
and there were many problems with the mail last weeks - virii etc.
maybe this explains... but hey!

People, start asking.
i will ask ! i need to build a database.i haven't built any databases
yet (i did access db's though)here's the questions i have:
Abstract:
the db will contain information about real estates (flats/houses etc.)
i thought in OOD terms, and came to:
address, person, estate  - data  objects or - tables.using these
terms, there will be relations between these tables.
i understand there's solution of simply putting it all into 1 huge
table. and search by simple or/and matches. what i don't unserstand is:
how do i decide how much to go down with the most basic tables, vs. one
huge table.
as someone pointed this out to be the normalization question.
Q1: where do i read about it ?

books/links appreciated.
real examples appreciated too.
Q2: which platform shall i use for the GUI frontend of this DB, given
that i chose the DBMS to be PostgreSQL.
i have written in: C, C++, Java
(i see C isn't much of a help in GUI...except maybe GTK frontend)
i think i also can handle Python.
which tools are there ? what you suggest ?
need Hebrew support, of course .. so if GUI supports - good for it.
Thanks in advance!

M.









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NIC - ping to but not from

[Evgeny Popov]

It is killing me 2 days already, on RH62 box whatever PCI NIC use ( RTL8139,
3C905C ):

I can ping from another box to Linux, but not from Linux to outside.
I get X packet transmitted add only 1 recieved.
Also i have correct arp entry for the target.

After ifconfig eth0 down/up it works !

I had similar problem in past, but solved it by disabling automatic resource
handling in BIOS.

Regards,
Evgeny

Comsec Publicom


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Re: ping

[Oded Arbel]

Then just
ping -c how many you'd like
and check the error code. if its non zero, then none of the packets
returned, else at least one packet returned. sound to me like the same
functionality.

Oded

--
Beauty unaware of itself is the most beautiful



- Original Message -
From: Noam Meltzer
To: guy keren
Cc: IGLU
Sent: Thursday, May 31, 2001 09:56
Subject: Re: ping


patching the original script sounds much more like what i need if i don't
find something else.
on the first look  it might seem like  ping -s on solaris is much better
than the default ping but thats not always the case.
lets assume that you need to get statistics on the status of the network.
statistics like, the host is up or down, just that no more than that. what
ping in solaris does is sending packets to a host until it responds or until
(i'm not sure) a certain time has been exceeded or X packets didn't return.
if one packet returns it's enough. in such cases the solaris' ping is much
more usefull and comfortable to use.


guy keren wrote:

On Thu, 31 May 2001, Noam Meltzer wrote:
Well guys thank you all... but that what i really didn't want... sctiptsi
can write my self.What i really wanted is to find out if you can get what
the ping binaryin solaris does not a scripts to emulate it.Is there such a
tool for linux?
a script _is_ a tool. what is the problem iwth writing this script
andinstalling it somewhere on the system? if yo want, you can turn this
intoa one-line perl script given to perl on the command line.there is no
difference between that and a binary program. btw, the way'ping' behaves on
linux by edfault is more useful then the way it does onsolaris (i.e. 'host
is alive'? that's much less useful then what 'ping -s'gives you on
solaris).btw, why do _you_ think the output on solaris is better then on
linux? forcustomer support via the phone? then tel the user to type 'ping -c
1' andread the output to you.--guyFor world domination - press 1, or dial
0, and please hold, for the creator. -- nob o.
dy=To
unsubscribe, send mail to [EMAIL PROTECTED] withthe word
unsubscribe in the message body, e.g., run the commandecho unsubscribe |
mail [EMAIL PROTECTED]


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Re: ping

[Dani Arbel]

You can always take the ping source and modify it to your own needs. no
big deal.
Dani

On Thu, 31 May 2001, Noam Meltzer wrote:

 Well guys thank you all... but that what i really didn't want... sctipts
 i can write my self.
 What i really wanted is to find out if you can get what the ping binary
 in solaris does not a scripts to emulate it.
 Is there such a tool for linux?
 
 Noam
 
 rcs wrote:
 
   Ooops!
   and
   if [ $# != 2 ]...
   should be
   if [ $# != 1 ]
  
   Sorry, it's been a long long day. here's the new code:
  
   #!/bin/sh
   if [ $# != 1 ]; then echo usage: $0 host; exit; fi
   ping -c 1 $1 /dev/null 21
   if [ $? == 0 ]
   then
echo $1 is alive
   else
echo $1 is not answering (to ICMP echo-request)
   fi
  
   Oleg Goldshmidt [EMAIL PROTECTED] wrote:
  
   rcs [EMAIL PROTECTED] writes:
  
   #!/bin/sh
   if [ $# != 2 ]; then echo usage: $0 host; exit; fi
   ping -c 1 $1
   if [ $? == 0 ]
   then
echo $0 is alive.
   else
echo $0 is not answering (to ICMP echo-request).
   fi
  
   $0 should be $1, shouldn't it?
  
   --
   Oleg Goldshmidt | [EMAIL PROTECTED]
   If it aint't broken it hasn't got enough features yet.
  
 
 
 
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Re: ping

[Noam Meltzer]

Well guys thank you all... but that what i really didn't want... sctipts
i can write my self.
What i really wanted is to find out if you can get what the ping binary
in solaris does not a scripts to emulate it.
Is there such a tool for linux?

Noam

rcs wrote:

  Ooops!
  and
  if [ $# != 2 ]...
  should be
  if [ $# != 1 ]
 
  Sorry, it's been a long long day. here's the new code:
 
  #!/bin/sh
  if [ $# != 1 ]; then echo usage: $0 host; exit; fi
  ping -c 1 $1 /dev/null 21
  if [ $? == 0 ]
  then
   echo $1 is alive
  else
   echo $1 is not answering (to ICMP echo-request)
  fi
 
  Oleg Goldshmidt [EMAIL PROTECTED] wrote:
 
  rcs [EMAIL PROTECTED] writes:
 
  #!/bin/sh
  if [ $# != 2 ]; then echo usage: $0 host; exit; fi
  ping -c 1 $1
  if [ $? == 0 ]
  then
   echo $0 is alive.
  else
   echo $0 is not answering (to ICMP echo-request).
  fi
 
  $0 should be $1, shouldn't it?
 
  --
  Oleg Goldshmidt | [EMAIL PROTECTED]
  If it aint't broken it hasn't got enough features yet.
 



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Re: ping

[guy keren]

On Thu, 31 May 2001, Noam Meltzer wrote:

 Well guys thank you all... but that what i really didn't want... sctipts
 i can write my self.
 What i really wanted is to find out if you can get what the ping binary
 in solaris does not a scripts to emulate it.
 Is there such a tool for linux?

a script _is_ a tool. what is the problem iwth writing this script and
installing it somewhere on the system? if yo want, you can turn this into
a one-line perl script given to perl on the command line.

there is no difference between that and a binary program. btw, the way
'ping' behaves on linux by edfault is more useful then the way it does on
solaris (i.e. 'host is alive'? that's much less useful then what 'ping -s'
gives you on solaris).

btw, why do _you_ think the output on solaris is better then on linux? for
customer support via the phone? then tel the user to type 'ping -c 1' and
read the output to you.

--
guy

For world domination - press 1,
 or dial 0, and please hold, for the creator. -- nob o. dy


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Re: ping

[Noam Meltzer]

patching the original script sounds much more like what i need if i don't find something else.
on the first look it might seem like ping -s on solaris is much better than the default ping but thats not always the case.
lets assume that you need to get statistics on the status of the network.
statistics like, the host is up or down, just that no more than that. what
ping in solaris does is sending packets to a host until it responds or until
(i'm not sure) a certain time has been exceeded or X packets didn't return.
if one packet returns it's enough. in such cases the solaris' ping is much
more usefull and comfortable to use.


guy keren wrote:
[EMAIL PROTECTED]">On Thu, 31 May 2001, Noam Meltzer wrote:
  Well guys thank you all... but that what i really didn't want... sctiptsi can write my self.What i really wanted is to find out if you can get what the ping binaryin solaris does not a scripts to emulate it.Is there such a tool for linux?
a script _is_ a tool. what is the problem iwth writing this script andinstalling it somewhere on the system? if yo want, you can turn this intoa one-line perl script given to perl on the command line.there is no difference between that and a binary program. btw, the way'ping' behaves on linux by edfault is more useful then the way it does onsolaris (i.e. 'host is alive'? that's much less useful then what 'ping -s'gives you on solaris).btw, why do _you_ think the output on solaris is better then on linux? forcustomer support via the phone? then tel the user to type 'ping -c 1' andread the output to you.--guy"For world domination - press 1, or dial 0, and please hold, for the creator." -- nob o. dy=To unsubscribe, send mail to [EMAIL PROTECTED] withthe word "unsubscribe" in the message body, e.g., run the commandecho unsubscribe | mail [EMAIL PROTECTED]

Re: ping

[R.C.S]

You want a good tool, you'll have to write one :)
maybe the following code will help you out, thought is sends tcp pings.
it's real 0day so you might find bugs, but it works.

// TCP Port pinger
// code by rasta

#include stdio.h
#include stdlib.h
#include unistd.h
#include string.h
#include sys/types.h
#include sys/socket.h
#include netinet/in.h
#include arpa/inet.h
#include netdb.h
#include errno.h

extern int h_errno;
//#include net.h

#define PORT 80
#define NUMP 1

resolve(const char *host)
{
 struct hostent *h;
 struct in_addr inp;
 if((inet_aton(host,inp))==0) {
  if((h=gethostbyname(host))==NULL) {
   herror(gethostbyname);
   exit(1);
  }
  memcpy((void *)inp.s_addr,(const void *)h-h_addr,h-h_length);
 }
 return (inp.s_addr);
}

int main(int argc, char **argv)
{
 int i, s, port, num, t, *tp;
 struct sockaddr_in sock;
 struct hostent *hostname;

 port=PORT;
 num=NUMP;
 t=1; tp=t;

 if(argc2) { 
  printf(usage: %s host [num pings] [port]\n,argv[0]); 
  exit(1); }

 if(argc2) port=atoi(argv[2]);
 if(argc3) num=atoi(argv[3]);


 sock.sin_family=AF_INET;
 sock.sin_port=htons(port);
 sock.sin_addr.s_addr=resolve(argv[1]);
 bzero((void *)(struct sockaddr *)sock.sin_zero,8);


 for(i=0;inum;i++) {
  if(!(s=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP))) {
   perror(socket); exit(1); }
  alarm(5);
  if((connect(s,(struct sockaddr *)sock,sizeof(struct sockaddr_in)))==-1) {
   perror(connect);
   shutdown(s,2);
   close(s);
   exit(1);
  }
  printf(host is up\n);
  shutdown(s,2);
  close(s);
  sleep(1);
 }
 return 0;
}

Noam Meltzer [EMAIL PROTECTED] wrote:
 patching the original script sounds much more like what i need if i 
 don't find something else.
 on the first look  it might seem like  ping -s on solaris is much better 
 than the default ping but thats not always the case.
 lets assume that you need to get statistics on the status of the 
 network. statistics like, the host is up or down, just that no more than 
 that. what ping in solaris does is sending packets to a host until it 
 responds or until (i'm not sure) a certain time has been exceeded or X 
 packets didn't return. if one packet returns it's enough. in such cases 
 the solaris' ping is much more usefull and comfortable to use.
 
 
 guy keren wrote:
 
  On Thu, 31 May 2001, Noam Meltzer wrote:
  
  Well guys thank you all... but that what i really didn't want... sctipts
  i can write my self.
  What i really wanted is to find out if you can get what the ping binary
  in solaris does not a scripts to emulate it.
  Is there such a tool for linux?
  
  
  a script _is_ a tool. what is the problem iwth writing this script and
  installing it somewhere on the system? if yo want, you can turn this into
  a one-line perl script given to perl on the command line.
  
  there is no difference between that and a binary program. btw, the way
  'ping' behaves on linux by edfault is more useful then the way it does on
  solaris (i.e. 'host is alive'? that's much less useful then what 'ping -s'
  gives you on solaris).
  
  btw, why do _you_ think the output on solaris is better then on linux? for
  customer support via the phone? then tel the user to type 'ping -c 1' and
  read the output to you.
  
  --
  guy
  
  For world domination - press 1,
   or dial 0, and please hold, for the creator. -- nob o. dy
  
  
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ping

[Noam Meltzer]

Hi!
I know that on Solaris the output of ping is host is alive or 
service not avaiable (or something like that)
i was wandering how i can achieve such answer in linux.

noam


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Re: ping

[rcs]

#!/bin/sh
if [ $# != 2 ]; then echo usage: $0 host; exit; fi
ping -c 1 $1
if [ $? == 0 ]
then
 echo $0 is alive.
else
 echo $0 is not answering (to ICMP echo-request).
fi

Noam Meltzer [EMAIL PROTECTED] wrote:
 Hi!
 I know that on Solaris the output of ping is host is alive or 
 service not avaiable (or something like that)
 i was wandering how i can achieve such answer in linux.
 
 noam
 
 
 =
 To unsubscribe, send mail to [EMAIL PROTECTED] with
 the word unsubscribe in the message body, e.g., run the command
 echo unsubscribe | mail [EMAIL PROTECTED]

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Re: ping

[Oleg Goldshmidt]

rcs [EMAIL PROTECTED] writes:

 #!/bin/sh
 if [ $# != 2 ]; then echo usage: $0 host; exit; fi
 ping -c 1 $1
 if [ $? == 0 ]
 then
  echo $0 is alive.
 else
  echo $0 is not answering (to ICMP echo-request).
 fi

$0 should be $1, shouldn't it?

-- 
Oleg Goldshmidt | [EMAIL PROTECTED] 
If it aint't broken it hasn't got enough features yet.

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Re: ping

[rcs]

Ooops!
and 
if [ $# != 2 ]...
should be 
if [ $# != 1 ]

Sorry, it's been a long long day. here's the new code:

#!/bin/sh
if [ $# != 1 ]; then echo usage: $0 host; exit; fi
ping -c 1 $1 /dev/null 21
if [ $? == 0 ]
then
 echo $1 is alive 
else
 echo $1 is not answering (to ICMP echo-request)
fi

Oleg Goldshmidt [EMAIL PROTECTED] wrote:
 rcs [EMAIL PROTECTED] writes:
 
  #!/bin/sh
  if [ $# != 2 ]; then echo usage: $0 host; exit; fi
  ping -c 1 $1
  if [ $? == 0 ]
  then
   echo $0 is alive.
  else
   echo $0 is not answering (to ICMP echo-request).
  fi
 
 $0 should be $1, shouldn't it?
 
 -- 
 Oleg Goldshmidt | [EMAIL PROTECTED] 
 If it aint't broken it hasn't got enough features yet.

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Join #shellcode on EFnet.
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Re: ping

[R.C.S]

Oleg Goldshmidt [EMAIL PROTECTED] wrote:
 rcs [EMAIL PROTECTED] writes:
 
  #!/bin/sh
  if [ $# != 2 ]; then echo usage: $0 host; exit; fi
  ping -c 1 $1
  if [ $? == 0 ]
  then
   echo $0 is alive.
  else
   echo $0 is not answering (to ICMP echo-request).
  fi
 
 $0 should be $1, shouldn't it?

Yea ofcource. 


 
 -- 
 Oleg Goldshmidt | [EMAIL PROTECTED] 
 If it aint't broken it hasn't got enough features yet.

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Re: ping

[Yotam Rubin]

ping does not natively make those 'deductions', be it is easy to write a 
wrapper that does that for you. Something like:
case `ping -qc 5 $1` in
 *'100% packet loss'*) 
   echo Target host $1 does not respond to ICMP echo requests.
 ;;
 *) 
   echo Target host $1 responds to ICMP echo requests.
 ;;
esac


On Tue, May 29, 2001 at 11:48:14PM -0700!@?#?%?, Noam Meltzer wrote:
 Hi!
 I know that on Solaris the output of ping is host is alive or 
 service not avaiable (or something like that)
 i was wandering how i can achieve such answer in linux.
 
 noam
 
 
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