Re: Question of Firewall & Mail Servers

[Pann McCuaig <pann@ourmanpann.com>]

On Fri, Sep 17, 1999 at 14:11, Doug Thistlethwaite wrote:

> I am working on adding a debian slink linux system as a fire wall to my
> existing company network.  When finished, we will have an ISDN router
> connected to the linux firewall machine and a separate network card
> connecting the internal network to the linux system.
> 
> The mail server will be inside of the firewall and needs to receive SMTP
> connections through the firewall.

> My question is how is this done?

There are (at least) two ways to do this. Another user has responded to
tell you how to punch a hole in your firewall for port 25. You can also
use a "store and forward" system to prevent anyone from outside your
network from talking directly to port 25 on your mail server.

One such system is smap, and another is smtpd. I've had good experience
with the latter, no experience with the former. If memory serves, I
selected smtpd because it was pretty much a drop-in on a debian slink
system that was the firewall.

I used rinetd on that system for punching holes in the firewall (port
22, ssh, for example).

http://www.obtuse.com/smtpd.html
http://www.boutell.com/rinetd/

Luck,
Pann
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