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Date:      Tue, 11 Nov 2003 10:36:09 +0100
From:      "Gorm J. Siiger" <>
Subject:   ipfw FWD, NAT and routing
Message-ID:  <20031111093609.GI94551@SonnIT.DK>

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I'm experimenting with a dual ISP setup using NAT, as eacy ISP has provided
me with a subnet of official IP adresses.

Network setup:

--------	--------
| ISP1 |	| ISP2 |
--------	--------
   |               |
   |    --------   |
   -----|  FW  |----

ISP1 LAN   :
ISP2 LAN   :
Server LAN :
Server IP on ISP1:
Server IP on LAN:
Server IP on ISP2:
Server IP on LAN:

The default gateway for the FW box is ISP1

I can connect to the whole world via ISP1 from the server with source IP but when I try to connect to a host via ISP2 from source
the TCP connection is very slow, and there is a lot of retransmissions.

If I change the FW's default gateway to ISP2 it works like a charm.

Any suggestions on how to fix this problem.

 unregistered_only yes

 ${fwcmd} add 400 divert natd all from any to any via ${isp0if}
 ${fwcmd} add 405 divert natd all from any to any via ${isp1if}
 ${fwcmd} add 505 fwd ip from to any

Gorm J. Siiger - SonnIT

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