From: Phillip Smith on
2009/11/18 Dhiraj Chatpar <dchatpar(a)gmail.com>:
> Dear Sir,
> I read your post on the postfix forum. I am a fan of yours after what
> solutions you gave regarding iptables and rotation of IPs. i tried doing
> that on my server and still get deferred from yahoo. Is there a way i can
> rotate my IPs by way of a script or something. Please advice me.
> Please also mention that iptables method.. will it send each email from the
> new ip i mention or just rotate the IPs? how does it work?
> Need your help
> Rgds
> Dhiraj

The IP tables rules I posted will Source NAT each *new* outbound
connection on port 25 to a different IP address. This should make each
new connection appear from a different IP address. It works at the TCP
level (layer 3) and as such is not aware of the SMTP transaction(s) at
Layer 4.

If your mail server is configured to deliver multiple messages per
SMTP session, then the IP address will not be cycled since they are
being delivered in the same single TCP connection.

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