[CentOS] Re: postfix tightening

Sun Apr 3 03:58:44 UTC 2005
Mark A. Lewis <mark at siliconjunkie.net>

>There is certainly nothing there
> to override the earlier RFC (which I've forgotten) that 
> specifies a similar recommendation but goes on to say that 
> the receiver MUST NOT reject the message based on an address 
> lookup mismatch for the HELO/EHLO name (obviously written by 
> someone who realized that multi-homed servers are common and 
> that corporate servers often live behind NAT firewalls and 
> don't even know the address that will be used the public side).
> --
>   Les Mikesell
>    les at futuresource.com
I believe you are referring to RFC 821:

The HELO receiver MAY verify that the HELO parameter really 
corresponds to the IP address of the sender. However, the receiver 
MUST NOT refuse to accept a message, even if the sender's HELO 
command fails verification.

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