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Date:      Mon, 29 Dec 2003 16:30:40 -0800 (PST)
From:      Terry Singh <>
Subject:   arp request problem with firewall
Message-ID:  <>

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this is my first post to freebsd questions. 


Internet -- WAN_IF | FIREWALL - 5.1 RELASE | LAN_IF -- LAN network

The WAN_IF has several public addresses as aliases. I have about 20 servers in
the LAN that require various services allowed to the public Internet. 

I basically am doing a "bimap" one to one mapping per server in the LAN.
This all works great, meaning I can surf etc etc from any LAN server to the
Internet and also, from the Internet I can get published services on LAN

Here's the problem:
I already mentioned that each server with a 192.168.50.x address is "bimap"ed
to a public address. The problem is that if I am on any of the LAN servers, and
want to connect to the public address of a server in the LAN, I CANNOT.
Now first of, I could connect using private addresses and of course this works
like it should. But our applications have real DNS names coded in the apps so I
need this to work. 

I know it has something to be with proxy arp so I even tried placing this line
in sysctl.conf:\
no luck.


Second problem
One of the LAN servers is a FTP server. From the Internet, I can only connect
using ACTIVE MODE even though I allow both 20/21/tcp inbound. Here's what
happens when passive mode is used: The initial connection is accepted, but then
the server sends its private address instead of its proper public address! Of
course it's not gonna work! So I forced active mode and voila! it worked.
What's the fix for this bugger? I now outbound FTP has some built-in proxy ftp
in freebsd but what about inbound?

thanks, tsingh.

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