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Date:      Fri, 1 Oct 2004 18:50:11 +1000
From:      "Steven Adams" <steve@drifthost.com>
To:        "'Subhro'" <subhro.kar@gmail.com>, <drift@freebsd.org>
Cc:        freebsd-questions@freebsd.org
Subject:   RE: IPFW Problem
Message-ID:  <20041001084847.EEFCD43D45@mx1.FreeBSD.org>
In-Reply-To: <b2807d0404093007355b40a34f@mail.gmail.com>

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I don't have an internal network.

This is a server with 1 gigabit network card on a gig link.

Im really confussed on whats happing then, because web browsing still works
but its blocking come packets..

I host 60sites+ so I cant pin it down to one site or nothing.

Anyone have any other ideas?

Steven Adams steve@drifthost.com 
DriftNet Web Services http://www.drifthost.com 
Home: +61 2 94274857
Fax: +61 2 94274857
Mobile +61 (0) 404 085644

-----Original Message-----
From: Subhro [mailto:subhro.kar@gmail.com] 
Sent: Friday, 1 October 2004 12:36 AM
To: drift@freebsd.org
Cc: steve@drifthost.com; freebsd-questions@freebsd.org
Subject: Re: IPFW Problem

On Thu, 30 Sep 2004 22:32:16 +1000, Steven Adams <steve@drifthost.com>
wrote:
> When I add
> 
> $fwcmd add allow ip from any to any established
> 
> The messages go away, but when I remove it they come back, I ran a tcpdump
> it seems most of the packet just have ACK set?

If this works for you then the keep-state is definitely not working
for you. Because when a SYN comes in, the state is saved in the
firewall dynamic states so that subsequent ACKs corresponding to that
SYN gets through without any problem.

<snip>

>===========================================================
> oif=bge0
> fwcmd=ipfw
> 
> $fwcmd -f flush
> 
> $fwcmd add check-state
> 
> $fwcmd add allow ip from any to any via lo0
> $fwcmd add deny ip from any to 127.0.0.0/8
> 
> $fwcmd add deny all from any to any frag in via $oif
> 
> $fwcmd add allow tcp from any to me
>
21,25,26,53,110,143,443,465,953,993,995,2082,2083,2086,2087,2089,2095,2096,2
> 627,6666,40000-49452
> in via $oif keep-state setup
> $fwcmd add allow tcp from any to me 80 setup keep-state
> $fwcmd add allow udp from me 53 to any keep-state
> $fwcmd add allow udp from any to any 53 keep-state
> 
> $fwcmd add allow all from me to any out via $oif setup keep-state
> 
> $fwcmd add deny all from any to any 137,138,139,67,68 in
> 
> $fwcmd add deny log all from me to any 22
> $fwcmd add deny log all from any to any

change this to $fwcmd add deny log all from any to any in xmit $oif
BTW, any good reason not to trust your internal network from sending
data through the firewall?

<snip>

Regards
S.

-- 
Subhro Sankha Kar
School of Information Technology
Block AQ-13/1 Sector V
ZIP 700091
India
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