IPFW Rule set question...

[Drew Robertson]

Thanks for your reply.

I don't understand what you mean when you say NAT modifications... meaning 
how the packets are changed on the gateway to allow them to be seen as 
transparent from behind??

When I do a netstat -an while connected remotley it shows the connection on 
SSH as coming from 203.10.10.38, but when I add a rule to allow everything 
from that net it still won't allow access...

I did add the rule before the divert, but i still couldn't connect until i 
added an allow all manually...

i also tried opening up the ssh port to everyone, with allow tcp from any to 
me 22 via tl0, but that wouldn't allow a connection either...

It's a bit confusing...

Thanks again,

D


>From: Lowell Gilbert <freebsd-questions-local at be-well.ilk.org>
>Reply-To: freebsd-questions at freebsd.org
>To: "Drew Robertson" <the_brothel at hotmail.com>
>CC: freebsd-questions at freebsd.org
>Subject: Re: IPFW Rule set question...
>Date: 24 Dec 2003 16:43:49 -0500
>
>"Drew Robertson" <the_brothel at hotmail.com> writes:
>
> > I have enabled SSH, TELNET and FTP on my freeBSD 4.8 box at home... it
> > is dual homed, 2 NICs one for the internal LAN one running my cable
> > modem.  Everything works fine on the internal side.
> >
> > When accessing the box using any of those apps from work, the system
> > looks to briefly connect and then returns a "Connection Lost" or
> > "Connection closed by remote host error".
> >
> > The command setup to allow in access is as follows...
> >
> > 820 allow log tcp from any to me 22 limit src-addr 4 in recv tl0 setup
> > 830 allow log tcp from any to me 23 limit src-addr 4 in recv tl0 setup
>
>I assume these are supposed to have "keep-state" in them.
>It *is* written that way in the full ruleset you posted lower down.
>
> > when this didn't work I added another command at the start of the
> > ruleset to just let everything in from a particular IP address range...
> >
> > 202 allow ip from 203.10.10.0/24 to any
> >
> > however this produced the same error...
> >
> > It wasn't until I allowed all from any to any that I was able to 
>connect...
>
>Then the packets aren't actually being seen as coming from that
>address.  Maybe you're running into NAT modifications?
>
> > When checking out the security log, it tells me that rule 820 is
> > allowing access to my computer at home...
>
>But only for SYN packets...
>
>
>--
>Lowell Gilbert, embedded/networking software engineer, Boston area:
>		resume/CV at http://be-well.ilk.org:8088/~lowell/resume/
>		username/password "public"

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