Theo Van Dinter wrote:
On Tue, Aug 15, 2006 at 08:41:27AM +1000, Guy Waugh wrote:
Aug 15 05:01:35 mailserver sendmail[13287]: k7EJ1YE7013287:
SYSERR(root): localhost.fabulous.com. config error: mail loops back to
me (MX problem?)
Do people actively combat this somehow?
I guess it depends how it got into your system in the first place.
If it's from some random outside machine sending you mail, why did the
MTA accept it in the first place? Typically MTAs only accept mail for
hosts/domains they consider "local" or for which they're configured
to relay. If "localhost.fabulous.com" isn't one of those two, I'd find
out why your MTA didn't just reject it.
The machine in question is one of our MXes. It's running some RBLs (and
clamav and SA), but a lot of spam still gets through (at least to clamav
and SA).
The above stuff appears in my logs when, for example, our MX receives
spam for an unknown local user and tries to bounce the mail back to the
sender. The sender domain's MX resolves to 127.0.0.1 (or similar), and
the above occurs. I was thinking of a test whereby something on my MTA
looks up the MX of every sender domain of every email, and if it
resolves to localhost, the email is rejected (discarded/whatever) at
that point.
