Subject: IPNAT
To: '' <>
From: Fishwick, Chris <>
List: tech-net
Date: 06/02/2001 13:51:16
Hi All,

I am probably being a little slow with this, but this is my situation:

ISP <----- ISDN -----> Cisco Router <--- NetBSD ---> |-Server
of Network

The Cisco box has a globally routable IP, the NetBSD box has both a globally
routable ( & non routable ( address.  The Server has
an IP address of and the rest of the workstations are all
within the 192.168.1.x range.  I need to be able to have the workstations on
the network talk to the internet freely, and also have the routable IP
address on the NetBSD box do some port forwarding to the internal server.
For instance, I need the NetBSD box to accept connections of port 25 and
forward them to the server, same for ports 80 & 110 so that services such as
SMTP, POP3 and WWW appear to the outside world, but while also blocking free
access to the server.

I am sure that this is really easy to do, but I am totally new to NetBSD,
and need to find the solution kind of urgently.  Any help would be
appreciated.  In the meantime, I will try and find some documentation on how
to do this quickly and easily..