[CentOS] postfix - reject of incoming mail due to helo check??

[Stephen Harris]

On Fri, Feb 03, 2012 at 12:21:28PM +0100, Kai Schaetzl wrote:
> many "false" positives. There is no definitive RFC requirement that the 
> mapping has to match. 

But it's a standard security feature (on Solaris NFS server it was
added around 1996, I think).  Without the match I could set my servers
IP address to be "mail.google.com".  No one should believe me unless
a forward lookup matches.  It is commonly considered "broken" for rDNS
to return a value that doesn't match forward DNS.

> false positive ratio is very low. Certainly lower for me than Sorbs (threw 
> out Sorbs years ago).

I, personally, use zen.spamhaus.org

-- 

rgds
Stephen