[ILUG] etrn & ipchains

[Stephen Shirley]

> Steve
> 
> Option 2 is what I will try as I don't want to leave PORT 25 open on the
> Firewall as we have to use static ip with etrn.
> Would I be correct in saying that ipmasqadm is the correct tool to use
> with ipchains.
> I will not be exploring this fully until friday as all our staff are on
> a junket to Paris leaving me to get a serious network overhaul done.
> 
> Regards Ger
> 

Unfortunately, either option means that port 25 will be left open.
The difference is in which machine will get connected to by an attempt
to open port 25 on the firewall. On the other hand, you know the ip
address of the mail server, or at the very least the block of 
possible ip addresses, and therefore you can set up ipchains to only
allow connection to port 25 from that address. 
To answer your other question, I've never used anything other
than ipchains itself to set up a firewall. I persume that 
ipmasqadm just makes it easier to tell ipchains what you want.

To do port-forwarding between machines, you need another package.
The one I used, and would reccomend, is tproxy, available at
ftp://ftp.nlc.net.au/pub/unix/transproxy/

Again, if you need any help with ipchains, or tproxy, just
send me a mail.
G'luck,

Steve