Re: [GTALUG] ppp inside private network, but no DNS returned?

[James Knott via talk]

On 2023-03-01 13:24, Stewart Russell via talk wrote:
I was slightly surprised how the old scripts I used for dialup over 20 
years (and a different country) ago were still used for LTE modem 
connections, complete with an even larger set of AT commands to 
control the device. I still think of AT commands as "Hayes" commands, 
even though Hayes themselves haven't existed this century. (Dennis 
Hayes still exists personally, as far as I know, as does his business 
partner Dale Heatherington - who retired at age 37 in the mid 80s, and 
seems to have had a great time since then.)


Years ago, I had a Nokia 2G phone (the old Rogers IS-136 network, before 
they switched to GSM) which could use the AT commands to act as a 
modem.  I never used it, as that was an extra cost service.




I guess ppp will be with us forever. I was pretty impressed that 
someone managed to implement a ppp wifi modem on the very cheap 
ESP8266 microcontroller. If you have a serial port, you can now talk 
(not very fast) over wifi: 
https://www.tindie.com/products/theoldnet/rs232-serial-wifi-modem-for-vintage-computers-v4/
(there's a github link to the source in there for folks who might 
build their own)


PPP is used in PPPoE, as in ADSL internet connections.  PPP is an 
official RFC spec and used in many places you never heard of.  For 
example with routers, you could use PPP over a T1 line.  You'd configure 
it in the CSU.  It's also covered in the Cisco CCNA.  If you want to get 
into the gritty details, you can read "Using & Managing PPP", from 
O'Reilly.  It's just a method of providing a layer 2 network over a 
serial connection.


BTW, when I got my first Internet connection (anyone remember io.org?), 
I used a SLIP connection, which was popular before PPP was commonly 
used.  SLIP required a static config, as it didn't provide connection 
info, as PPP does.


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Re: [GTALUG] ppp inside private network, but no DNS returned?

[Stewart Russell via talk]

On Wed, Mar 1, 2023 at 1:08 AM William Park via talk 
wrote:

> I don't do dialup anymore.  But, looking at my old PPP setup (I'm
> surprised I still have it), 'dns-addr' is assigned in /etc/ppp/options.
>

Yeah, there's a lot going on in ppp systems.

I was slightly surprised how the old scripts I used for dialup over 20
years (and a different country) ago were still used for LTE modem
connections, complete with an even larger set of AT commands to control the
device. I still think of AT commands as "Hayes" commands, even though Hayes
themselves haven't existed this century. (Dennis Hayes still exists
personally, as far as I know, as does his business partner Dale
Heatherington - who retired at age 37 in the mid 80s, and seems to have had
a great time since then.)

I guess ppp will be with us forever. I was pretty impressed that someone
managed to implement a ppp wifi modem on the very cheap ESP8266
microcontroller. If you have a serial port, you can now talk (not very
fast) over wifi:
https://www.tindie.com/products/theoldnet/rs232-serial-wifi-modem-for-vintage-computers-v4/
(there's a github link to the source in there for folks who might build
their own)

 Stewart
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Re: [GTALUG] ppp inside private network, but no DNS returned?

[William Park via talk]

I don't do dialup anymore.  But, looking at my old PPP setup (I'm 
surprised I still have it), 'dns-addr' is assigned in /etc/ppp/options.


On 2023-02-28 14:50, Stewart Russell via talk wrote:

Hey - we've got a fun little problem happening right now.

We're connecting a Linux box via LTE to a client's private network. They 
want us to connect to a host on that network and upload files via sftp. 
We've demonstrated that all of this works with every other LTE network, 
but in their walled garden LTE network, they're not returning any DNS 
server, so we can't find the host at all. This network does not have 
access to public DNS.


Does one usually have to poke a ppp connection a little more to get 
useful routing information, or should we have "just got" all the gateway 
and DNS details on first connection?


  Stewart
(as you can tell, I'm not a network person, but we might appreciate 
finding one and paying for support)



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Re: [GTALUG] ppp inside private network, but no DNS returned?

[Stewart C. Russell via talk]

On 28/02/2023 16.22, James Knott via talk wrote:

On 2023-02-28 16:21, Stewart Russell via talk wrote:
Also, these are devices that are on a network that couldn't reach 
OneDrive.


Maybe you could try sneakernet.  
They're in sealed boxes, up high, possibly near high-voltage equipment. 
You go first, I'll wait ...

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Re: [GTALUG] ppp inside private network, but no DNS returned?

[James Knott via talk]

On 2023-02-28 16:21, Stewart Russell via talk wrote:
Also, these are devices that are on a network that couldn't reach 
OneDrive.


Maybe you could try sneakernet.  
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Re: [GTALUG] ppp inside private network, but no DNS returned?

[Stewart Russell via talk]

On Tue, Feb 28, 2023 at 4:13 PM William Park via talk 
wrote:

> Ah, they want you to debug for them for free.
>

This is absolutely not the case. Never attribute to malice that which can
be more easily explained by massive bureaucracy. Also, these are devices
that are on a network that couldn't reach OneDrive.

 Stewart
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Re: [GTALUG] ppp inside private network, but no DNS returned?

[William Park via talk]

Ah, they want you to debug for them for free.  If the client is big 
enough, then, yes, do complimentary service.  If not, then just upload 
an encrypted zipfile to OneDrive (or whatever), and tell them to download.


On 2023-02-28 15:28, Stewart Russell via talk wrote:

Thanks, all. Yes, there has to be a DNS, but there's a chance that

 1. we haven't been told what it is;
 2. our connection/hardware hasn't been authorized to connect to it or
know what it is
(yes, it's that kind of place)

There is no other internet connection. We've been given a host name, not 
an internal IP address to connect to. We're also hearing that we're the 
first folks connecting via this ultra-locked down LTE network for IOT 
devices, so maybe they forgot to provision some services


On Tue, Feb 28, 2023 at 3:11 PM Alvin Starr via talk > wrote:


PPP does not require a dns server address to be provided.
But most folks do provide one because it would make for LOTS of support
calls to not hand out your DNS servers.

Is there a DNS on the network that your connecting to at all?
If not then you wll likely be forecd to use the /etc/hosts file to add
in the IP addresses of the target systems.



On 2023-02-28 14:50, Stewart Russell via talk wrote:
 > Hey - we've got a fun little problem happening right now.
 >
 > We're connecting a Linux box via LTE to a client's private network.
 > They want us to connect to a host on that network and upload
files via
 > sftp. We've demonstrated that all of this works with every other LTE
 > network, but in their walled garden LTE network, they're not
returning
 > any DNS server, so we can't find the host at all. This network does
 > not have access to public DNS.
 >
 > Does one usually have to poke a ppp connection a little more to get
 > useful routing information, or should we have "just got" all the
 > gateway and DNS details on first connection?
 >
 >  Stewart
 > (as you can tell, I'm not a network person, but we might appreciate
 > finding one and paying for support)
 >
 >
 > ---
 > Post to this mailing list talk@gtalug.org 
 > Unsubscribe from this mailing list
https://gtalug.org/mailman/listinfo/talk


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Netvel Inc.                   ||   Cell:  (416)806-0133
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Re: [GTALUG] ppp inside private network, but no DNS returned?

[Dave Collier-Brown via talk]

If the externally-reachable network is intended for the IOT devices to connect to, they may well be 
using IP addresses only.  Call it the "DMZ network" or "external network".

They probably have a "management network" that goes to different interfaces, 
and which has DNS services for their own convenience. I've seen setups like this

internet --> DMZ network --> host <- management network <- firewall <- office 
network

--dave



On 2/28/23 15:28, Stewart Russell via talk wrote:
Thanks, all. Yes, there has to be a DNS, but there's a chance that

 1.  we haven't been told what it is;
 2.  our connection/hardware hasn't been authorized to connect to it or know 
what it is
(yes, it's that kind of place)

There is no other internet connection. We've been given a host name, not an 
internal IP address to connect to. We're also hearing that we're the first 
folks connecting via this ultra-locked down LTE network for IOT devices, so 
maybe they forgot to provision some services

On Tue, Feb 28, 2023 at 3:11 PM Alvin Starr via talk 
mailto:talk@gtalug.org>> wrote:
PPP does not require a dns server address to be provided.
But most folks do provide one because it would make for LOTS of support
calls to not hand out your DNS servers.

Is there a DNS on the network that your connecting to at all?
If not then you wll likely be forecd to use the /etc/hosts file to add
in the IP addresses of the target systems.



On 2023-02-28 14:50, Stewart Russell via talk wrote:

Hey - we've got a fun little problem happening right now.

We're connecting a Linux box via LTE to a client's private network.
They want us to connect to a host on that network and upload files via
sftp. We've demonstrated that all of this works with every other LTE
network, but in their walled garden LTE network, they're not returning
any DNS server, so we can't find the host at all. This network does
not have access to public DNS.

Does one usually have to poke a ppp connection a little more to get
useful routing information, or should we have "just got" all the
gateway and DNS details on first connection?

 Stewart
(as you can tell, I'm not a network person, but we might appreciate
finding one and paying for support)


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al...@netvel.net  ||

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Re: [GTALUG] ppp inside private network, but no DNS returned?

[Alvin Starr via talk]

You can enable debugging in your pppd config which may help.
There is also a "usepeerdns" pppd option that may give you some joy.

I have a client who has a prison as a customer and they have lots of 
unusual requirements for computers inside the wire.
I have debugged hundreds of PPP clients/servers over the years so if you 
want some help feel free to reach out and contact me.




On 2023-02-28 15:28, Stewart Russell via talk wrote:

Thanks, all. Yes, there has to be a DNS, but there's a chance that

 1. we haven't been told what it is;
 2. our connection/hardware hasn't been authorized to connect to it or
know what it is
(yes, it's that kind of place)

There is no other internet connection. We've been given a host name, 
not an internal IP address to connect to. We're also hearing that 
we're the first folks connecting via this ultra-locked down LTE 
network for IOT devices, so maybe they forgot to provision some services


On Tue, Feb 28, 2023 at 3:11 PM Alvin Starr via talk  
wrote:


PPP does not require a dns server address to be provided.
But most folks do provide one because it would make for LOTS of
support
calls to not hand out your DNS servers.

Is there a DNS on the network that your connecting to at all?
If not then you wll likely be forecd to use the /etc/hosts file to
add
in the IP addresses of the target systems.



On 2023-02-28 14:50, Stewart Russell via talk wrote:
> Hey - we've got a fun little problem happening right now.
>
> We're connecting a Linux box via LTE to a client's private network.
> They want us to connect to a host on that network and upload
files via
> sftp. We've demonstrated that all of this works with every other
LTE
> network, but in their walled garden LTE network, they're not
returning
> any DNS server, so we can't find the host at all. This network does
> not have access to public DNS.
>
> Does one usually have to poke a ppp connection a little more to get
> useful routing information, or should we have "just got" all the
> gateway and DNS details on first connection?
>
>  Stewart
> (as you can tell, I'm not a network person, but we might appreciate
> finding one and paying for support)
>
>
> ---
> Post to this mailing list talk@gtalug.org
> Unsubscribe from this mailing list
https://gtalug.org/mailman/listinfo/talk

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Re: [GTALUG] ppp inside private network, but no DNS returned?

[Stewart Russell via talk]

Thanks, all. Yes, there has to be a DNS, but there's a chance that

   1. we haven't been told what it is;
   2. our connection/hardware hasn't been authorized to connect to it or
   know what it is
   (yes, it's that kind of place)

There is no other internet connection. We've been given a host name, not an
internal IP address to connect to. We're also hearing that we're the first
folks connecting via this ultra-locked down LTE network for IOT devices, so
maybe they forgot to provision some services

On Tue, Feb 28, 2023 at 3:11 PM Alvin Starr via talk 
wrote:

> PPP does not require a dns server address to be provided.
> But most folks do provide one because it would make for LOTS of support
> calls to not hand out your DNS servers.
>
> Is there a DNS on the network that your connecting to at all?
> If not then you wll likely be forecd to use the /etc/hosts file to add
> in the IP addresses of the target systems.
>
>
>
> On 2023-02-28 14:50, Stewart Russell via talk wrote:
> > Hey - we've got a fun little problem happening right now.
> >
> > We're connecting a Linux box via LTE to a client's private network.
> > They want us to connect to a host on that network and upload files via
> > sftp. We've demonstrated that all of this works with every other LTE
> > network, but in their walled garden LTE network, they're not returning
> > any DNS server, so we can't find the host at all. This network does
> > not have access to public DNS.
> >
> > Does one usually have to poke a ppp connection a little more to get
> > useful routing information, or should we have "just got" all the
> > gateway and DNS details on first connection?
> >
> >  Stewart
> > (as you can tell, I'm not a network person, but we might appreciate
> > finding one and paying for support)
> >
> >
> > ---
> > Post to this mailing list talk@gtalug.org
> > Unsubscribe from this mailing list
> https://gtalug.org/mailman/listinfo/talk
>
> --
> Alvin Starr   ||   land:  (647)478-6285
> Netvel Inc.   ||   Cell:  (416)806-0133
> al...@netvel.net  ||
>
> ---
> Post to this mailing list talk@gtalug.org
> Unsubscribe from this mailing list
> https://gtalug.org/mailman/listinfo/talk
>


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Re: [GTALUG] ppp inside private network, but no DNS returned?

[Alvin Starr via talk]

PPP does not require a dns server address to be provided.
But most folks do provide one because it would make for LOTS of support 
calls to not hand out your DNS servers.


Is there a DNS on the network that your connecting to at all?
If not then you wll likely be forecd to use the /etc/hosts file to add 
in the IP addresses of the target systems.




On 2023-02-28 14:50, Stewart Russell via talk wrote:

Hey - we've got a fun little problem happening right now.

We're connecting a Linux box via LTE to a client's private network. 
They want us to connect to a host on that network and upload files via 
sftp. We've demonstrated that all of this works with every other LTE 
network, but in their walled garden LTE network, they're not returning 
any DNS server, so we can't find the host at all. This network does 
not have access to public DNS.


Does one usually have to poke a ppp connection a little more to get 
useful routing information, or should we have "just got" all the 
gateway and DNS details on first connection?


 Stewart
(as you can tell, I'm not a network person, but we might appreciate 
finding one and paying for support)



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Re: [GTALUG] ppp inside private network, but no DNS returned?

[D. Hugh Redelmeier via talk]

How do they want you to find things on their net?

Do they have a DNS server?  Surely yes.

They should put it into the PPP negotiation.  Why would they not?

If they won't put it into PPP, maybe you have to monkey with 
/etc/resolv.conf (systemd will argue with you).

If they don't have a DNS, what do they use?
Perhaps you can use mDNS / bonjour / whatever?

Does the device have another internet connection at the same time?  At 
other times?  If so, it might need a DNS solution that works for that 
connection.
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Re: [GTALUG] ppp inside private network, but no DNS returned?

[Dave Collier-Brown via talk]

I wonder if

 1.  they decided to not use DNS, in which case they would have given you an IP 
address, or
 2.  they decided to not tell outsiders where the DNS server was, so that the 
outsider would have to be given an IP address, or
 3.  they didn't tell outsiders where the DNS server was because they didn't 
know they needed to, and just took the default (;-))

--dave


On 2/28/23 14:58, Stewart Russell via talk wrote:


On Tue, Feb 28, 2023 at 2:55 PM James Knott via talk 
mailto:talk@gtalug.org>> wrote:



Doesn't the PPP server normally provide the DNS address?
https://www.rfc-editor.org/rfc/rfc1877.html#section-1.1

I'd have expected so, but that RFC says "By default, no primary DNS address is 
provided."

thanks




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Re: [GTALUG] ppp inside private network, but no DNS returned?

[James Knott via talk]

On 2023-02-28 14:58, Stewart Russell via talk wrote:



On Tue, Feb 28, 2023 at 2:55 PM James Knott via talk  
wrote:


>
Doesn't the PPP server normally provide the DNS address?
https://www.rfc-editor.org/rfc/rfc1877.html#section-1.1


I'd have expected so, but that RFC says "By default, no primary DNS 
address is provided."



Can you reach hosts by IP address?
PPP does not work the same way as a LAN does.  On a LAN, DNS would 
normally be provided by the DHCP server.  However, since PPP links 
provide the IP address, no DHCP server is used.  Also, I believe there's 
a slightly different DNS provided for Windows clients.  How is that 
network set up?  Perhaps for Windows clients and you're using Linux?



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Re: [GTALUG] ppp inside private network, but no DNS returned?

[Stewart Russell via talk]

On Tue, Feb 28, 2023 at 2:55 PM James Knott via talk 
wrote:

> >
> Doesn't the PPP server normally provide the DNS address?
> https://www.rfc-editor.org/rfc/rfc1877.html#section-1.1


I'd have expected so, but that RFC says "By default, no primary DNS address
is provided."

thanks
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Re: [GTALUG] ppp inside private network, but no DNS returned?

[James Knott via talk]

On 2023-02-28 14:50, Stewart Russell via talk wrote:

Hey - we've got a fun little problem happening right now.

We're connecting a Linux box via LTE to a client's private network. 
They want us to connect to a host on that network and upload files via 
sftp. We've demonstrated that all of this works with every other LTE 
network, but in their walled garden LTE network, they're not returning 
any DNS server, so we can't find the host at all. This network does 
not have access to public DNS.


Does one usually have to poke a ppp connection a little more to get 
useful routing information, or should we have "just got" all the 
gateway and DNS details on first connection?


 Stewart
(as you can tell, I'm not a network person, but we might appreciate 
finding one and paying for support)




Doesn't the PPP server normally provide the DNS address?
https://www.rfc-editor.org/rfc/rfc1877.html#section-1.1

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[GTALUG] ppp inside private network, but no DNS returned?

[Stewart Russell via talk]

Hey - we've got a fun little problem happening right now.

We're connecting a Linux box via LTE to a client's private network. They
want us to connect to a host on that network and upload files via sftp.
We've demonstrated that all of this works with every other LTE network, but
in their walled garden LTE network, they're not returning any DNS server,
so we can't find the host at all. This network does not have access to
public DNS.

Does one usually have to poke a ppp connection a little more to get useful
routing information, or should we have "just got" all the gateway and DNS
details on first connection?

 Stewart
(as you can tell, I'm not a network person, but we might appreciate finding
one and paying for support)
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