Use a different IP for sending mail

If you find yourself in a pinch and you need a temporary fix when your primary IP is blacklisted, use the following iptables rule:

/sbin/iptables -t nat -A POSTROUTING -p tcp --dport 25 -j SNAT --to-source [desired outgoing ip]

Keep in mind, however, that you will need to adjust any applicable SPF records for your domains since your e-mail will appear to be leaving via one of the secondary IP's on your server. Also, remember that this is only a temporary fix - you should find out why you were blacklisted and eliminate that problem as soon as possible.

This entry was posted on 27/08/2007 (Monday) at 9:13 pm and is filed under Uncategorized. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

Printed from: http://rackerhacker.com/2007/08/27/use-a-different-ip-for-sending-mail/ .
© Major Hayden 2010.

1 Comment »

Ashutosh says:
15.07.10 at 23:32
Hello sir,
I want to use a different IP for sending mail. But i don't know where and how to use that code (/sbin/iptables -t nat -A POSTROUTING -p tcp --dport 25 -j SNAT --to-source [desired outgoing ip]) in asp.net.
Please HELP !!!