Emails Randomly Reaching Destination

Mark Sapiro mark at msapiro.net
Sat Mar 20 19:51:08 GMT 2010


Vernon Webb wrote:

> Is the domain name checked at all when receiving emails or is it based
> solely on the IP address of the originating IP that determines if it is
> RBLed or not?


What domain name?

The domain of the server's HELO/EHLO? The domain of the MAIL FROM
(envelope sender)? The domain from an rDNS lookup of the IP? The domain
of an MX record associated with one of the previous domains?

It would seem that all but the last of these domains would probably be
your domain, not the domain of any XO servers, and therefore not a
blacklisted domain in any case, and while it is not possible to know
what tests any specific mail recipient might apply, it doesn't seem
likely that servers would be not accepting/delivering mail based on some
MX server with such a tenuous connection to the actual sender.

Furthermore, the EHLO/HELO and MAIL FROM domains are easily spoofed so
why would a recipient server look at those rather than the sender's IP
which is the most reliable identifying information it has?

-- 
Mark Sapiro <mark at msapiro.net>        The highway is for gamblers,
San Francisco Bay Area, California    better use your sense - B. Dylan



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