Simon Wilson wrote:
I'm running Postfix 2.3.3 on CentOS 5.3 x64 (Postfix installed from
CentOS repository). Firstly thank you to the writers for a great piece
of software... :)
Postconf -n:
[]
Setup works a treat, has been running great for a few weeks. I sent an
email to about 10 people, 2 of the email addresses were wrong. For one
of them I got a bounce message in my mailbox telling me it was wrong (I
had typed @yahoo.com.uk instead of @yahoo.co.uk). The other one I got
nothing (I had typed @talktalk.com instead of talktalk.net) so wasn't
aware I'd mistyped but I have just noticed a message sitting in the
Postfix mail queue in Webmin (for the talktalk.net one) saying
"Status: Host or domain name not found. Name service error for
name=talktalk.com type=MX: Host not found, try again"
So my question is why did I get a message that one was wring and not the
other? Do I need to change config somehow?
There are two types of problems you're seeing, from about a million of
possibilities. ;)
With yahoo.com.uk postfix was able to contact the remote servers instantly,
and got definitive answer that the address does not exist, so postfix sent
the bounce message back to you as soon as it knew the answer, or almost
immediately.
But with talktalk.com the situation is different. The DNS servers for that
domain does not work. Postfix tried to figure out where to send that email
to, but is unable to - because there's no one to answer. So Postfix tried
and retried, but still got no answer - nor positive nor negative. So it
does not know what to do with the address in question. And the best it can
do is to retry for some time, maybe the remote servers are just down and will
come back in a near future, maybe there's some communication problems that
will be resolved soon and so on. Postfix will keep trying for up to
maximal_queue_lifetime (which is 5days by default) and will finally return
the email back to you telling it wasn't able to figure out what to do with
it.
So basically, there's nothing for you to do, the thing work as designed. There's
one more parameter you can tweak if you like - it's delay_warning_time.
/mjt
