Redirect SMTP Requests

ALInux · 08-03-2006, 06:07 AM

Hi
I use outlook on my laptop to send an receive emails, however when Iam at work I have to setup a certain smtp A in hte account options when I go home i have to setup another smtp B. So what I would like to do is to keep smtp A in my outlook options, and to use the DEBIAN box I have at home to redirect traffic going sent to smtp A from my laptop to smtp B.

I have tried the following, but it does not seem to work

iptables -t nat -A PREROUTING -i eth1 -s $MY_IP -p tcp --dport 25 -j REDIRECT --to "smtpB":25

peter_robb · 08-03-2006, 06:11 AM

Does smtp A have an AUTH option to allow authorised smtp?

telnet smtpA 25
ehlo somename

and look for a 250 AUTH response.

This way you can use just 1 smtp server.

REDIRECT sends to localhost not externally.
You need to use DNAT instead.

ALInux · 08-03-2006, 07:41 AM

Thanks Peter

iptables -t nat -A PREROUTING -i eth1 -s $MY_IP -p tcp --dport 25 -j DNAT --to "smtpB":25

Worked quite well for me