[Dnsmasq-discuss] [solved] Re: Finding actual DNS server used

2017-01-15 Thread Lars Noodén 
On 01/16/2017 12:23 AM, Weedy wrote:
> On 15 January 2017 at 17:15, Albert ARIBAUD 
> wrote:
>> Hi Weedy,
>> 
>> Le Sun, 15 Jan 2017 17:04:37 -0500 Weedy  a
>> écrit:
> [snip]
>>> 
>>> http://www.thekelleys.org.uk/dnsmasq/docs/dnsmasq-man.html#lbAG
>>> 
>>> An API of sorts was added some time last year
>> 
>> I've gone through the NOTES section you are referring to, but I
>> don't see exactly which API you are referring to. Could you provide
>> more precise indications?
> 
> I was talking about "statistics are also available in the DNS as 
> answers to queries of class CHAOS and type TXT in domain bind".
> Which is why I said API of sorts.
[snip]

Thanks. That's it.  I somehow missed it there in the manual page:

When it receives a SIGUSR1, dnsmasq writes  statistics
to  the  system log.  … For each upstream server
it  gives  the  number  of  queries sent, and the
number which resulted in an error.
…

That gives me the information I was looking for regarding verifying
which server dnsmasq is using.

Regards,
Lars

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Re: [Dnsmasq-discuss] Finding actual DNS server used

2017-01-15 Thread Albert ARIBAUD 
Hi Weedy,

Le Sun, 15 Jan 2017 17:23:18 -0500
Weedy  a écrit:

> >> http://www.thekelleys.org.uk/dnsmasq/docs/dnsmasq-man.html#lbAG
> >>
> >> An API of sorts was added some time last year  
> >
> > I've gone through the NOTES section you are referring to, but I
> > don't see exactly which API you are referring to. Could you provide
> > more precise indications?  
> 
> I was talking about "statistics are also available in the DNS as
> answers to queries of class CHAOS and type TXT in domain bind". Which
> is why I said API of sorts.

Hey, it does indeed work!

$ dig +short chaos txt servers.bind
"fe80:::::%enp4s0#53 144 0" "192.168.x.x#53 126 0"

> You already went into detail on DBus control, that would be considered
> a more legit API

I would not say one is 'more legit' than the other, as both are
legitimate uses of valid protocol features; and yours has the advantage
that it's easier to parse.

Thanks!

Amicalement,
-- 
Albert.

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Re: [Dnsmasq-discuss] Finding actual DNS server used

2017-01-15 Thread Weedy 
On 15 January 2017 at 17:15, Albert ARIBAUD  wrote:
> Hi Weedy,
>
> Le Sun, 15 Jan 2017 17:04:37 -0500
> Weedy  a écrit:
>
>> On 15 January 2017 at 03:21, Albert ARIBAUD 
>> wrote:
>> > Hi Chris,
>> >
>> > Le Sat, 14 Jan 2017 19:27:28 +
>> > Chris Green  a écrit:
>> >
>> > (re getting dnsmasq to say which upstream servers it uses)
>> >
>> >> Why is is so difficult to provide this information?  At the very
>> >> least it would provide a confidence check that all is working as
>> >> intended. It might very well help if something isn't working too.
>> >
>> > It is not difficult at all to get this information. It's just that
>> > dnsmasq does not provide any "API" to get it, because it's easy to
>> > get it  otherwise for diagnosis purposes.
>>
>> http://www.thekelleys.org.uk/dnsmasq/docs/dnsmasq-man.html#lbAG
>>
>> An API of sorts was added some time last year
>
> I've gone through the NOTES section you are referring to, but I don't
> see exactly which API you are referring to. Could you provide more
> precise indications?

I was talking about "statistics are also available in the DNS as
answers to queries of class CHAOS and type TXT in domain bind". Which
is why I said API of sorts.

You already went into detail on DBus control, that would be considered
a more legit API

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Re: [Dnsmasq-discuss] Duplicate IPs assigned to devices with similar MAC (same vendor)

2017-01-15 Thread Oleg Brodkin 

How one find what identifier client sent? DNSMASQ logs show names that client 
provided:

Jan 15 08:12:26 dnsmasq-dhcp[13128]: 2689251041 client provides name: 
nuc_labtest_1

Jan 13 17:33:35 dnsmasq-dhcp[12864]: 792419227 client provides name: g5br2d2


On Sun, Jan 15, 2017 at 02:54:18PM +, Simon Kelley wrote:
> -BEGIN PGP SIGNED MESSAGE-
> Hash: SHA256
> 
> The most likely explanation is that both devices are supplying the
> same client-id, which trumps MAC address as the system indentifier.
> Are they both running the same system image?
> 
> Cheers,
> 
> Simon.

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Re: [Dnsmasq-discuss] Finding actual DNS server used

2017-01-15 Thread Weedy 
On 14 January 2017 at 07:40, Lars Noodén  wrote:
> How can I get an already running instance of Dnsmasq to tell which DNS
> servers it is using to resolve new queries upstream?

It's in the man page. Also I think we added special TXT or something
queries last year.

Sun Jan 15 15:01:00 2017 cron.info crond[976]: USER root pid 9833 cmd
killall -USR1 dnsmasq
Sun Jan 15 15:01:00 2017 daemon.info dnsmasq[2350]: time 1484510460
Sun Jan 15 15:01:00 2017 daemon.info dnsmasq[2350]: cache size 4096,
0/3244 cache insertions re-used unexpired cache entries.
Sun Jan 15 15:01:00 2017 daemon.info dnsmasq[2350]: queries forwarded
1565, queries answered locally 16006
Sun Jan 15 15:01:00 2017 daemon.info dnsmasq[2350]: server
66.163.0.161#53: queries sent 882, retried or failed 9
Sun Jan 15 15:01:00 2017 daemon.info dnsmasq[2350]: server
208.72.120.204#53: queries sent 903, retried or failed 8
Sun Jan 15 15:01:00 2017 daemon.info dnsmasq[2350]: server
205.151.222.251#53: queries sent 316, retried or failed 0
Sun Jan 15 15:01:00 2017 daemon.info dnsmasq[2350]: server
216.254.141.2#53: queries sent 325, retried or failed 4
Sun Jan 15 15:01:00 2017 daemon.info dnsmasq[2350]: server 8.8.4.4#53:
queries sent 328, retried or failed 2
Sun Jan 15 15:01:00 2017 daemon.info dnsmasq[2350]: server
206.248.154.170#53: queries sent 330, retried or failed 0
Sun Jan 15 15:01:00 2017 daemon.info dnsmasq[2350]: server
206.248.154.22#53: queries sent 365, retried or failed 6

Why is the thread 20 replies long without answering the original question

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Re: [Dnsmasq-discuss] Finding actual DNS server used

2017-01-15 Thread Weedy 
On 15 January 2017 at 03:21, Albert ARIBAUD  wrote:
> Hi Chris,
>
> Le Sat, 14 Jan 2017 19:27:28 +
> Chris Green  a écrit:
>
> (re getting dnsmasq to say which upstream servers it uses)
>
>> Why is is so difficult to provide this information?  At the very least
>> it would provide a confidence check that all is working as intended.
>> It might very well help if something isn't working too.
>
> It is not difficult at all to get this information. It's just that
> dnsmasq does not provide any "API" to get it, because it's easy to get
> it  otherwise for diagnosis purposes.

http://www.thekelleys.org.uk/dnsmasq/docs/dnsmasq-man.html#lbAG

An API of sorts was added some time last year

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Re: [Dnsmasq-discuss] Finding actual DNS server used

2017-01-15 Thread Albert ARIBAUD 
Hi Chris,

Le Sun, 15 Jan 2017 20:31:28 +
Chris Green  a écrit:

> On Sun, Jan 15, 2017 at 04:54:11PM +0100, Albert ARIBAUD wrote:
> > Bonjour,
> > 
> > Le Sun, 15 Jan 2017 12:36:47 +
> > Chris Green  a écrit:
> >   
> > > On Sun, Jan 15, 2017 at 12:14:42PM +0100, Albert ARIBAUD wrote:  
> > > > > > - read the configuration file(s) dnsmasq uses and find
> > > > > > "server=" lines in it, and read the /etc/resolv* tree, if
> > > > > > dnsmasq uses them, and that will give the list of servers
> > > > > > dnmasq uses at any point in time.
> > > > > >   
> > > > > There aren't any! These are systems where dnsmasq is run by
> > > > > Network Manager rather than directly, thus there is no spcific
> > > > > dnsmasq configuration file.
> > > > 
> > > > ... and then the configuration is known from the dnsmasq process
> > > > command line. So let me amend my statement above: "... read the
> > > > configuration options, from the dnsmasq process command line if
> > > > it contains any, and from the configuration file or files if
> > > > applicable".   
> > > chris@t430$ ps -ef | grep dnsmasq
> > > nobody1579  1031  0 Jan14 ?
> > > 00:00:01 /usr/sbin/dnsmasq --no-resolv --keep-in-foreground
> > > --no-hosts --bind-interfaces
> > > --pid-file=/var/run/NetworkManager/dnsmasq.pid
> > > --listen-address=127.0.1.1 --cache-size=0 --conf-file=/dev/null
> > > --proxy-dnssec
> > > --enable-dbus=org.freedesktop.NetworkManager.dnsmasq
> > > --conf-dir=/etc/NetworkManager/dnsmasq.d chris@t430$ 
> > > 
> > > 
> > > ... and there's nothing in /etc/NetworkManager/dnsmasq.d  
> > 
> > Then Network Manager sets the DNS via DBus, as the configuration
> > (on command line) allows it. You can most probably find which DNS
> > servers are set by spying on DBus, using dbus-monitor. You can even
> > set up a bash script which shows a list of them in real time.
> >   
> Is there any description anywhere of how to do this?

A ready-made solution with zero effort? Non, there is none.

A solution with some effort? In my case, 10 minutes of searching how to
filter dbus-monitor by interface, starting with near-zero knowledge of
DBus, and strictly zero knowledge of dbus-monitor, and ending up with
the following proof-of-concept running on my machine:

1. Run this command in a shell:

sudo dbus-monitor --system \
"interface=org.freedesktop.NetworkManager.dnsmasq"

(your interface may not be the same. Run

dbus-send --system --dest=org.freedesktop.DBus
--type=method_call --print-reply /org/freedesktop/DBus
org.freedesktop.DBus.ListNames | grep dnsmasq

and you'll know the interface to use.

2. Force a connection renewal through Network Manager (or by unplugging
   and replugging the client's RJ45 if that's how it gets network
   access).

3. See the dbus-monitor running in the shell display dumps of the
   SetServersEx method calls, complete with server IPs as arguments.

If you want to automate that, you'll need to do some parsing. Or maybe
use Python, which provides a dbus module; this should make extracting
the method arguments easier.

Amicalement,
-- 
Albert.

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Re: [Dnsmasq-discuss] Finding actual DNS server used

2017-01-15 Thread Chris Green 
On Sun, Jan 15, 2017 at 04:54:11PM +0100, Albert ARIBAUD wrote:
> Bonjour,
> 
> Le Sun, 15 Jan 2017 12:36:47 +
> Chris Green  a écrit:
> 
> > On Sun, Jan 15, 2017 at 12:14:42PM +0100, Albert ARIBAUD wrote:
> > > > > - read the configuration file(s) dnsmasq uses and find "server="
> > > > >   lines in it, and read the /etc/resolv* tree, if dnsmasq uses
> > > > > them, and that will give the list of servers dnmasq uses at any
> > > > > point in time.
> > > > > 
> > > > There aren't any! These are systems where dnsmasq is run by
> > > > Network Manager rather than directly, thus there is no spcific
> > > > dnsmasq configuration file.  
> > > 
> > > ... and then the configuration is known from the dnsmasq process
> > > command line. So let me amend my statement above: "... read the
> > > configuration options, from the dnsmasq process command line if it
> > > contains any, and from the configuration file or files if
> > > applicable". 
> > chris@t430$ ps -ef | grep dnsmasq
> > nobody1579  1031  0 Jan14 ?00:00:01 /usr/sbin/dnsmasq
> > --no-resolv --keep-in-foreground --no-hosts --bind-interfaces
> > --pid-file=/var/run/NetworkManager/dnsmasq.pid
> > --listen-address=127.0.1.1 --cache-size=0 --conf-file=/dev/null
> > --proxy-dnssec
> > --enable-dbus=org.freedesktop.NetworkManager.dnsmasq
> > --conf-dir=/etc/NetworkManager/dnsmasq.d chris@t430$ 
> > 
> > 
> > ... and there's nothing in /etc/NetworkManager/dnsmasq.d
> 
> Then Network Manager sets the DNS via DBus, as the configuration
> (on command line) allows it. You can most probably find which DNS
> servers are set by spying on DBus, using dbus-monitor. You can even set
> up a bash script which shows a list of them in real time.
> 
Is there any description anywhere of how to do this?

-- 
Chris Green

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[Dnsmasq-discuss] Fwd: dhcpv6 and clients in Oracle VirtualBox

2017-01-15 Thread e9hack+dnsmasq 
Hi,

VirtualBox exchanges the source/destination mac of all client packets to the 
mac of the host and vice versa. If a config
entry is searched by dnsmasq, first the duid will be compared. If no matching 
entry is found, the mac address is used
instead. Since no duid is configured for my clients in VirtualBox, dnsmasq 
searches for a matching mac. The packet
contains the host's mac, dnsmasq uses the config entry for the host. The client 
gets the name of the host. Dnsmasq can
not use the source mac of a packet to configure something.

Regards
Hartmut


 Weitergeleitete Nachricht 
Betreff: dhcpv6 and clients in Oracle VirtualBox
Datum: Thu, 12 Jan 2017 17:26:59 +0100
Von: e9hack 
An: dnsmasq-discuss@lists.thekelleys.org.uk

Hi,

I've some trouble with clients in VirtualBox (Linux and Windows 10). The host 
runs Windows 7. I create dhcp-host entries
for all machines:

dhcp-host=aa:aa:aa:aa:aa:aa,id:00:01:00:01:aa:aa:aa:aa:aa:aa:aa:aa:aa:aa,192.168.255.100,[::0:0:1234:100],host-windows
dhcp-host=bb:bb:bb:bb:bb:bb,192.168.255.110,[::0:0:1234:110],vbox-windows
dhcp-host=cc:cc:cc:cc:cc:cc,192.168.255.120,vbox-linux

If I start a client in VirtualBox, it does hi-jack the dhcp6 name of the host. 
Both windows machines are using the same
iaid. With 'ipconfig /renew6', I can retrieve the name for ipv6. All machines 
provide a name by its own. It is the same
name, which is configured for dnsmasq. If I add a duid and a ipv6 address, it 
doesn't occur. The ipv4 name isn't
affected. The second dhcp-host entry maybe wrong, because it contains an ipv6 
address but no duid.

Regards,
Hartmut

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Re: [Dnsmasq-discuss] Finding actual DNS server used

2017-01-15 Thread Albert ARIBAUD 
Bonjour,

Le Sun, 15 Jan 2017 12:36:47 +
Chris Green  a écrit:

> On Sun, Jan 15, 2017 at 12:14:42PM +0100, Albert ARIBAUD wrote:
> > > > - read the configuration file(s) dnsmasq uses and find "server="
> > > >   lines in it, and read the /etc/resolv* tree, if dnsmasq uses
> > > > them, and that will give the list of servers dnmasq uses at any
> > > > point in time.
> > > > 
> > > There aren't any! These are systems where dnsmasq is run by
> > > Network Manager rather than directly, thus there is no spcific
> > > dnsmasq configuration file.  
> > 
> > ... and then the configuration is known from the dnsmasq process
> > command line. So let me amend my statement above: "... read the
> > configuration options, from the dnsmasq process command line if it
> > contains any, and from the configuration file or files if
> > applicable". 
> chris@t430$ ps -ef | grep dnsmasq
> nobody1579  1031  0 Jan14 ?00:00:01 /usr/sbin/dnsmasq
> --no-resolv --keep-in-foreground --no-hosts --bind-interfaces
> --pid-file=/var/run/NetworkManager/dnsmasq.pid
> --listen-address=127.0.1.1 --cache-size=0 --conf-file=/dev/null
> --proxy-dnssec
> --enable-dbus=org.freedesktop.NetworkManager.dnsmasq
> --conf-dir=/etc/NetworkManager/dnsmasq.d chris@t430$ 
> 
> 
> ... and there's nothing in /etc/NetworkManager/dnsmasq.d

Then Network Manager sets the DNS via DBus, as the configuration
(on command line) allows it. You can most probably find which DNS
servers are set by spying on DBus, using dbus-monitor. You can even set
up a bash script which shows a list of them in real time.

Amicalement,
-- 
Albert.

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Re: [Dnsmasq-discuss] Duplicate IPs assigned to devices with similar MAC (same vendor)

2017-01-15 Thread Simon Kelley 
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA256

The most likely explanation is that both devices are supplying the
same client-id, which trumps MAC address as the system indentifier.
Are they both running the same system image?

Cheers,

Simon.


On 14/01/17 16:28, Oleg Brodkin wrote:
> # dnsmasq --version Dnsmasq version 2.76  Copyright (c) 2000-2016
> Simon Kelley # Lease time 48 hours
> 
> DNSMASQ server has been in our office for last 4-5 years, and
> mostly no issues with assigning IPs. Except there are two recent
> devices in our lab from the same vendor, and the server dishes them
> out duplicate IPs. Any ideas on what is going on and how to fix it?
> Thank you
> 
> Oleg
> 
> -- DEVICE 1 Jan 13 17:33:23 dnsmasq-dhcp[12864]: 328676717 sent
> size:  4 option: 54 server-identifier  10.111.222.6 Jan 13 17:33:23
> dnsmasq-dhcp[12864]: 328676717 sent size:  4 option:  1 netmask
> 255.255.248.0 Jan 13 17:33:23 dnsmasq-dhcp[12864]: 328676717 sent
> size:  4 option: 28 broadcast  10.111.223.255 Jan 13 17:33:23
> dnsmasq-dhcp[12864]: 328676717 sent size: 16 option: 15 domain-name
> xxx.com Jan 13 17:33:23 dnsmasq-dhcp[12864]: 328676717 sent size:
> 4 option:  6 dns-server  10.111.222.6 Jan 13 17:33:23
> dnsmasq-dhcp[12864]: 328676717 sent size:  4 option:  3 router
> 10.111.222.1 Jan 13 17:33:35 dnsmasq-dhcp[12864]: 792419227
> available DHCP range: 10.111.216.10 -- 10.111.219.250 Jan 13
> 17:33:35 dnsmasq-dhcp[12864]: 792419227 client provides name:
> g5br2d2 Jan 13 17:33:35 dnsmasq-dhcp[12864]: 792419227
> DHCPDISCOVER(eth0) f4:4d:30:60:73:40 Jan 13 17:33:35
> dnsmasq-dhcp[12864]: 792419227 tags: eth0 Jan 13 17:33:35
> dnsmasq-dhcp[12864]: 792419227 DHCPOFFER(eth0) 10.111.218.130
> f4:4d:30:60:73:40 Jan 13 17:33:35 dnsmasq-dhcp[12864]: 792419227
> requested options: 1:netmask, 3:router, 12:hostname,
> 15:domain-name, Jan 13 17:33:35 dnsmasq-dhcp[12864]: 792419227
> requested options: 6:dns-server, 33:static-route,
> 121:classless-static-route, Jan 13 17:33:35 dnsmasq-dhcp[12864]:
> 792419227 requested options: 42:ntp-server, 101 Jan 13 17:33:35
> dnsmasq-dhcp[12864]: 792419227 next server: 10.111.222.6 Jan 13
> 17:33:35 dnsmasq-dhcp[12864]: 792419227 sent size:  1 option: 53 
> message-type  2 Jan 13 17:33:35 dnsmasq-dhcp[12864]: 792419227 sent
> size:  4 option: 54 server-identifier  10.111.222.6 Jan 13 17:33:35
> dnsmasq-dhcp[12864]: 792419227 sent size:  4 option: 51 lease-time
> 2d Jan 13 17:33:35 dnsmasq-dhcp[12864]: 792419227 sent size:  4
> option: 58 T1 1d -- Jan 13 17:33:35 dnsmasq-dhcp[12864]: 792419227
> sent size:  4 option:  1 netmask  255.255.248.0 Jan 13 17:33:35
> dnsmasq-dhcp[12864]: 792419227 sent size:  4 option: 28 broadcast
> 10.111.223.255 Jan 13 17:33:35 dnsmasq-dhcp[12864]: 792419227 sent
> size: 16 option: 15 domain-name  xxx.com Jan 13 17:33:35
> dnsmasq-dhcp[12864]: 792419227 sent size:  8 option: 42 ntp-server
> 10.111.222.18, 10.111.222.22 Jan 13 17:33:35 dnsmasq-dhcp[12864]:
> 792419227 sent size:  4 option:  6 dns-server  10.111.222.6 Jan 13
> 17:33:35 dnsmasq-dhcp[12864]: 792419227 sent size:  4 option:  3 
> router  10.111.222.1 Jan 13 17:33:35 dnsmasq-dhcp[12864]: 792419227
> available DHCP range: 10.111.216.10 -- 10.111.219.250 Jan 13
> 17:33:35 dnsmasq-dhcp[12864]: 792419227 client provides name:
> g5br2d2 Jan 13 17:33:35 dnsmasq-dhcp[12864]: 792419227
> DHCPREQUEST(eth0) 10.111.218.130 f4:4d:30:60:73:40 Jan 13 17:33:35
> dnsmasq-dhcp[12864]: 792419227 tags: eth0 Jan 13 17:33:35
> dnsmasq-dhcp[12864]: 792419227 DHCPACK(eth0) 10.111.218.130 
> f4:4d:30:60:73:40 g5br2d2 Jan 13 17:33:35 dnsmasq-dhcp[12864]:
> 792419227 requested options: 1:netmask, 3:router, 12:hostname,
> 15:domain-name, Jan 13 17:33:35 dnsmasq-dhcp[12864]: 792419227
> requested options: 6:dns-server, 33:static-route,
> 121:classless-static-route, Jan 13 17:33:35 dnsmasq-dhcp[12864]:
> 792419227 requested options: 42:ntp-server, 101 Jan 13 17:33:35
> dnsmasq-dhcp[12864]: 792419227 next server: 10.111.222.6 Jan 13
> 17:33:35 dnsmasq-dhcp[12864]: 792419227 sent size:  1 option: 53 
> message-type  5 Jan 13 17:33:35 dnsmasq-dhcp[12864]: 792419227 sent
> size:  4 option: 54 server-identifier  10.111.222.6 Jan 13 17:33:35
> dnsmasq-dhcp[12864]: 792419227 sent size:  4 option: 51 lease-time
> 2d Jan 13 17:33:35 dnsmasq-dhcp[12864]: 792419227 sent size:  4
> option: 58 T1 1d
> 
> 
> -- DEVICE 2 Jan 13 14:12:23 dnsmasq-dhcp[12619]: 457454147 sent
> size:  4 option: 54 server-identifier  10.111.222.6 Jan 13 14:12:23
> dnsmasq-dhcp[12619]: 457454147 sent size:  4 option:  1 netmask
> 255.255.248.0 Jan 13 14:12:23 dnsmasq-dhcp[12619]: 457454147 sent
> size:  4 option: 28 broadcast  10.111.223.255 Jan 13 14:12:23
> dnsmasq-dhcp[12619]: 457454147 sent size: 16 option: 15 domain-name
> xxx.com Jan 13 14:12:23 dnsmasq-dhcp[12619]: 457454147 sent size:
> 4 option:  6 dns-server  10.111.222.6 Jan 13 14:12:23
> dnsmasq-dhcp[12619]: 457454147 sent size:  4 option:  3 router
> 10.111.222.1 Jan 13 14:12:31

Re: [Dnsmasq-discuss] Finding actual DNS server used

2017-01-15 Thread Chris Green 
On Sun, Jan 15, 2017 at 12:14:42PM +0100, Albert ARIBAUD wrote:
> > > - read the configuration file(s) dnsmasq uses and find "server="
> > >   lines in it, and read the /etc/resolv* tree, if dnsmasq uses them,
> > >   and that will give the list of servers dnmasq uses at any point in
> > >   time.
> > >   
> > There aren't any! These are systems where dnsmasq is run by Network
> > Manager rather than directly, thus there is no spcific dnsmasq
> > configuration file.
> 
> ... and then the configuration is known from the dnsmasq process command
> line. So let me amend my statement above: "... read the configuration
> options, from the dnsmasq process command line if it contains any, and
> from the configuration file or files if applicable".
> 
chris@t430$ ps -ef | grep dnsmasq
nobody1579  1031  0 Jan14 ?00:00:01 /usr/sbin/dnsmasq
--no-resolv --keep-in-foreground --no-hosts --bind-interfaces
--pid-file=/var/run/NetworkManager/dnsmasq.pid
--listen-address=127.0.1.1 --cache-size=0 --conf-file=/dev/null
--proxy-dnssec --enable-dbus=org.freedesktop.NetworkManager.dnsmasq
--conf-dir=/etc/NetworkManager/dnsmasq.d
chris@t430$ 


... and there's nothing in /etc/NetworkManager/dnsmasq.d

-- 
Chris Green

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Re: [Dnsmasq-discuss] Finding actual DNS server used

2017-01-15 Thread Chris Green 
On Sat, Jan 14, 2017 at 05:43:38PM -0500, Jim Alles wrote:
>As far as the desktop OS, a user can override the DNS entries that DHCP
>provides.

Not easily on most modern systems.  This is really where we came in!

All my xubuntu Linux boxes have the following in /etc/resolv.conf :-

# Dynamic resolv.conf(5) file for glibc resolver(3) generated by 
resolvconf(8)
# DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
nameserver 127.0.1.1
search zbmc.eu

I.e. the nameserver is 'me' and somewhere in the guts of the Network
Manager and dnsmasq configuration is something that specifies the
upstream server.

It's definitely *not* trivial to change the DNS being used.

-- 
Chris Green

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Re: [Dnsmasq-discuss] Finding actual DNS server used

2017-01-15 Thread Albert ARIBAUD 
Le Sun, 15 Jan 2017 09:58:38 +0100
Albert ARIBAUD  a écrit:

> Speaking of which, my first hunch re your problem is that it's not a
> dnsmasq problem, but a problem with the client's networking
> configuration. I suspect it connects through some VPN and gets an
> additional (or replacement) DNS, and that at some point the VPN
> connection goes bad and the client reverts (in part or in full) to its
> original DNS.

... or it could be that the VPN connection still runs OK but your
client screwed up its DNS setup upon renewal of its local DHCP lease.

Amicalement,
-- 
Albert.

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Re: [Dnsmasq-discuss] Finding actual DNS server used

2017-01-15 Thread Albert ARIBAUD 
Hi Lars,

Le Sun, 15 Jan 2017 10:21:01 +0200
Lars Noodén  a écrit:

> On 01/15/2017 09:55 AM, Albert ARIBAUD wrote:
> > Hi Lars,
> > 
> > Le Sat, 14 Jan 2017 20:18:13 +0200
> > Lars Noodén  a écrit:
> >...  
> >>  Because it's not my system and it is remote, I
> >> have to go step by step, slowly.  
> > 
> > ... Do you mean that you have good control of the remote system but
> > have to go there physically to run tests, or that you do not have
> > control of the system and must ask someone else to perform tests
> > there? This makes a difference in the way you can run your tests  
> 
> I have to describe the steps in e-mail and they are then carried out
> on site by a non-technical person.

Argh.

> >> Since everything on that system, in
> >> regards to DNS, is going via Dnsmasq, I'd like to see what it has
> >> loaded and is using.  
> > 
> > This bring me back to your description of the bug above: "somewhere
> > early on the DNS fails". What do you mean with that? Did you check
> > that the client keeps sinding DNS requests to your dnsmasq?  
> 
> The client application (Blink) will apparently default to Google's DNS
> if it cannot connect to the server right away.  What's happening is
> that half the time DNS replies, half the time it times out.  Thus the
> client can start to register with the SIP server, but then fails to
> publish its presence or be able to initiate a call.
> 
> > ... Or is
> > it that they come back from your dnsmasq with an error code for
> > domains which you know your dns should resolve properly?  
> 
> It seems to be this -- sometimes.
> 
> So is the short answer that there's no direct or easy way to poll a
> running Dnsmasq instance and see what it's pointing to?  If so, then
> I'll not bother the list more with this issue.  However, may I put in
> a feature request if there is a wish list?

See my other replies, but I'll make the main suggestion: the way to get
the info you want (and more, which might be useful for your diagnostics)
is to run tcpdump on the dnsmasq host on the "any' interface (or run
two tcpdumps, one on the interface used to talk to the client, one on
the interface used to talk to the Internet) with a capture filter set
for DHCP and DNS protocols, and write the capture into a file (or two,
if running two tcpdump instances). Then if you have two captures you
can use Wireshark's mergecap tool to merge them into a single one. Last,
you open the single capture file in Wireshark and see:

- whether your client was sent out a DHCP reply configuring DNS servers

- which DNS requests your client sent to dnsmasq

- which DNS requests your dnsmasq sent to which upstream server

- which DNS replies your dnsmasq received from which upstream server

- which DNS replies your client received from dnsmasq

That's the info you're asking for (of course, I assume you have control
of the host running dnsmasq) and much more. The method can be useful
for diagnosing other network or protocol issues as well.

Speaking of which, my first hunch re your problem is that it's not a
dnsmasq problem, but a problem with the client's networking
configuration. I suspect it connects through some VPN and gets an
additional (or replacement) DNS, and that at some point the VPN
connection goes bad and the client reverts (in part or in full) to its
original DNS.

In any case, the test above will give you a hint about that too: if you
see that the client stops sending requests at some point, you can
pretty much conclude it stopped using your dnsmasq as its DNS (you can
even know when it last did, and compare that with logs from the client
if you can get the non-tech person to do it.

BTW: I suspect there is no way to get the non-tech person to install a
remote access client (even ssh would be enough) and also no way for
you to get root privileges on it?

> Regards,
> /Lars

Amicalement,
-- 
Albert.

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Re: [Dnsmasq-discuss] Finding actual DNS server used

2017-01-15 Thread Lars Noodén 
On 01/15/2017 09:55 AM, Albert ARIBAUD wrote:
> Hi Lars,
> 
> Le Sat, 14 Jan 2017 20:18:13 +0200
> Lars Noodén  a écrit:
>...
>>  Because it's not my system and it is remote, I
>> have to go step by step, slowly.
> 
> ... Do you mean that you have good control of the remote system but
> have to go there physically to run tests, or that you do not have
> control of the system and must ask someone else to perform tests there?
> This makes a difference in the way you can run your tests

I have to describe the steps in e-mail and they are then carried out on
site by a non-technical person.

>> Since everything on that system, in
>> regards to DNS, is going via Dnsmasq, I'd like to see what it has
>> loaded and is using.
> 
> This bring me back to your description of the bug above: "somewhere
> early on the DNS fails". What do you mean with that? Did you check
> that the client keeps sinding DNS requests to your dnsmasq?

The client application (Blink) will apparently default to Google's DNS
if it cannot connect to the server right away.  What's happening is that
half the time DNS replies, half the time it times out.  Thus the client
can start to register with the SIP server, but then fails to publish its
presence or be able to initiate a call.

> ... Or is
> it that they come back from your dnsmasq with an error code for domains
> which you know your dns should resolve properly?

It seems to be this -- sometimes.

So is the short answer that there's no direct or easy way to poll a
running Dnsmasq instance and see what it's pointing to?  If so, then
I'll not bother the list more with this issue.  However, may I put in a
feature request if there is a wish list?

Regards,
/Lars

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Re: [Dnsmasq-discuss] Finding actual DNS server used

2017-01-15 Thread Albert ARIBAUD 
Hi Chris,

Le Sat, 14 Jan 2017 19:27:28 +
Chris Green  a écrit:

(re getting dnsmasq to say which upstream servers it uses)

> Why is is so difficult to provide this information?  At the very least
> it would provide a confidence check that all is working as intended.
> It might very well help if something isn't working too.

It is not difficult at all to get this information. It's just that
dnsmasq does not provide any "API" to get it, because it's easy to get
it  otherwise for diagnosis purposes.

For diagnosis, the operator can:

- read the configuration file(s) dnsmasq uses and find "server="
  lines in it, and read the /etc/resolv* tree, if dnsmasq uses them,
  and that will give the list of servers dnmasq uses at any point in
  time.

- log DNS queries, which will give the additional info about
  which client actually queried dnsmasq, which queries were cached vs
  sent upstream (to which server), and what the answer was.

- run tcpdump or wireshark on the dnsmasq host or on the DNS client (or
  both for troubleshooting e.g. timing-related issues). This will give
  a full view of DNS exchanges on the considerd machine, to the last
  bit, litterally.

So, from a diagnosis point of view, pulling the actual list of servers
from a running dnsmasq is not that much of a need.

I don't mean to say that such an "API" would be unneeded for other
requirements than network troubleshooting, and if it existed, I would
use and suggest it for troubleshooting too; but here, I mean to say
that helping solving Lars' problem does not require such an "API".

I feel that Lars' question was more "How can I troubleshoot my possibly
dnsmasq-related issue?" rather than "How can I find which servers my
dnsmasq uses?", and for this, we have the means above, which emcompass
the one Lars asks for and go well beyond -- plus, the first step to
troubleshooting an issue is to get the situation as precise as
possible, possibly ignoring the initially assumed cause (here the list
of upstream servers may be actually correct and the issue may be on the
client side, so the "API" question should be set aside, and getting a
more precise view of the issue should come first).

> For example if my machine can't connect to another machine on the LAN
> but can see the outside world it suggests it's getting DNS from
> something other than my Pi DNS server.  If I could check what DNS it
> is using then it would confirm that either it has got it's DNS set up
> from somewhere else or that it has got the right DNS (the Pi) but that
> the Pi is set up wrong somehow.

This case can be tested (and boy do I know it) with the host command on
the client as Jim suggested (although I personally use dig).

Amicalement,
-- 
Albert.

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