[ILUG] etrn & ipchains

[gerodonoghue at sigma-sl.ie]

On Tue, 5 Sep 2000 gerdono at eircom.net wrote:

> I have configured a firewall using ipchains kernel 2.2.16
> everything works except for my mail delivery. Mail Server is on
another server and use ETRN deliver to eircom.
> ETRN command is traversing the firewall no problem but returning mail
only comes as far as the firewall machine and does not get back to Mail
Server.
> Mail Server is VPOP3 (NT Server)
> I think my problem is due to the messages been delivered on a
different port ??
> Anyone got any ideas or config something similar
>
> regards ger donohue
>

>Hi,
>I persume that you're using ip_masq. The problem is that
>when eircom try to deliver the mail, they're making
>an unsolicated connection as far as the firewall is concerned.
>This means that eircom's connection is not being forwarded to your
>machine. Instead it is trying to connect to port 25 on the
>firewall. What you need to do is one of two things:

>1. Setup sendmail on the firewall so that it will forward
all incoming mail to your machine.

>2. Install port forwarding and set it up to forward all
connections to port 25 on the firewall to port 25 on your machine.

>If you need any help, just send me a mail.

>Steve

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