Firewall Wizards mailing list archives

Re: FreeBSD 4.9 ipfw natd -- Port Forwarding


From: Adam Humphrey <hump () casualritual com>
Date: Mon, 28 Jun 2004 18:05:41 -0700

I tried the ipfw fwd command as well with no success.  It was forwarding the
packets perfectly but they were still addressed to the outside IP address of
my freeBSD server and my internal web server was dropping them because they
were not addressed to its IP.

Thanks for the help.

Regards,

Adam


From: Ng Pheng Siong <ngps () netmemetic com>
Date: Tue, 29 Jun 2004 08:22:41 +0800
To: Adam Humphrey <hump () casualritual com>
Cc: <firewall-wizards () honor icsalabs com>
Subject: Re: [fw-wiz] FreeBSD 4.9 ipfw natd -- Port Forwarding

On Fri, Jun 25, 2004 at 05:27:18PM -0700, Adam Humphrey wrote:
Natd.conf:
redirect_port tcp 192.168.1.101:80 80

But now my web logs show everything coming from my firewall's external IP
address and not the actual IP of the request.

How do I get the original IP for the request to pass though my firewall and
get my log files displaying the appropriate source IP addresses?

I use 'ipfw fwd', no NAT. I don't see the problem you describe. In my case
the packets are being forwarded to a RFC 1918-addressed jail within the
same box. Purely from a packet flow perspective I think there is no
difference between this and forwarding to an external server, although I
can't rule out the involvement of some magic kernel knobs and I haven't
read the code in a while.

Example from my /etc/rc.firewall.rules:

  add <number> fwd 192.168.x.x tcp from any to x.x.x.x 80 keep-state setup

See manpage for more info on 'fwd'.

HTH. Cheers.

-- 
Ng Pheng Siong <ngps () netmemetic com>

http://firewall.rulemaker.net -+- Version Control for Cisco PIX & Netscreen
http://sandbox.rulemaker.net/ngps -+- M2Crypto, ZServerSSL/Zope, Blog



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