GNU bug report logs - #48753
iptables example update

Previous Next

To add a comment to this bug, you must first unarchive it, by sending
a message to control AT debbugs.gnu.org, with unarchive 48753 in the body.
You can then email your comments to 48753 AT debbugs.gnu.org in the normal way.

Toggle the display of automated, internal messages from the tracker.

Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Eric Brown <ecbrown <at> ericcbrown.com>
To: guix-patches <at> gnu.org
Subject: iptables example update
Date: Sun, 30 May 2021 22:07:07 +0100

[Message part 1 (text/plain, inline)]

Dear List,

I have often puzzled over the iptables example that is given in the Guix manual.

It seems that this rule would allow someone to ssh in, but would not
practically allow ssh *outward* because the session would not be able to
receive a response.

I've added what I think is a line that fixes the issue.

Best regards,
Eric

[0001-doc-Updated-iptables-example.patch (text/x-diff, attachment)]

Message #10 received at 48753-done <at> debbugs.gnu.org (full text, mbox):

From: Arun Isaac <arunisaac <at> systemreboot.net>
To: Eric Brown <ecbrown <at> ericcbrown.com>, 48753-done <at> debbugs.gnu.org
Subject: Re: [bug#48753] iptables example update
Date: Fri, 04 Jun 2021 00:16:49 +0530

[Message part 1 (text/plain, inline)]

Hi Eric,

I wrote the iptables service and documentation. So, the mistake is
entirely due to my poor grasp of iptables! :-)

I have applied your patch, and pushed to master. Thanks!

Cheers,
Arun

[signature.asc (application/pgp-signature, inline)]

Message #13 received at 48753-done <at> debbugs.gnu.org (full text, mbox):

From: "Eric Brown" <ecbrown <at> ericcbrown.com>
To: "Arun Isaac" <arunisaac <at> systemreboot.net>, 48753-done <at> debbugs.gnu.org
Subject: Re: [bug#48753] iptables example update
Date: Sun, 06 Jun 2021 13:52:57 -0500

On Thu, Jun 3, 2021, at 1:46 PM, Arun Isaac wrote:
> 
> Hi Eric,
> 
> I wrote the iptables service and documentation. So, the mistake is
> entirely due to my poor grasp of iptables! :-)
> 
> I have applied your patch, and pushed to master. Thanks!
> 
> Cheers,
> Arun
> 
> Attachments:
> * signature.asc



Hi Arun,

Thank you for applying the patch, I think it’s much better. Truthfully i am relieved that you are an iptables newbie and so am I!

I think there could still be some work done to this recommendation.  For example, when I use this updated iptables firewall selection, I am unable to telnet into ports open on localhost.   An example is that I am a heavy user of VNC/SSH tunnel connections and it doesn’t let me do that, it blocks e.g. port 5902.    (A similar naive rule in nftables does let this work!!!)

But so many examples are given in iptables (esp. WireGuard stuff) and so if you have no objections, I would like to take a further look and maybe even ask around as to what the ‘ufw allow ssh’ behavior vis-a-vis iptables best practices.

Best regards,
Eric

Message #16 received at 48753-done <at> debbugs.gnu.org (full text, mbox):

From: Arun Isaac <arunisaac <at> systemreboot.net>
To: Eric Brown <ecbrown <at> ericcbrown.com>, 48753-done <at> debbugs.gnu.org
Subject: Re: [bug#48753] iptables example update
Date: Wed, 16 Jun 2021 12:48:41 +0530

[Message part 1 (text/plain, inline)]

Hi Eric,

> Thank you for applying the patch, I think it’s much better. Truthfully
> i am relieved that you are an iptables newbie and so am I!

:-P

> I think there could still be some work done to this recommendation.
> For example, when I use this updated iptables firewall selection, I am
> unable to telnet into ports open on localhost.  An example is that I
> am a heavy user of VNC/SSH tunnel connections and it doesn’t let me do
> that, it blocks e.g. port 5902.  (A similar naive rule in nftables
> does let this work!!!)

I'm not able to reproduce this. I built and started a container with an
ssh server on port 5902. And, I was able to connect fine with
telnet. Could you describe the precise steps, configuration, etc. to
reproduce this issue?

> But so many examples are given in iptables (esp. WireGuard stuff) and
> so if you have no objections, I would like to take a further look and
> maybe even ask around as to what the ‘ufw allow ssh’ behavior
> vis-a-vis iptables best practices.

Sure, please do! You don't need my permission for that! :-)

Regards,
Arun

[signature.asc (application/pgp-signature, inline)]

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.