We are running sendmail8.10.1 on Solaris 7.
And our primary MX record is pointing to the above host.
Our second MX recond is pointing to our ISP mailhost, which seems
not check the sender's domain is resolvable or not.
Recently some inbound emails get delayed for 3 days.
It first tried to send to our primary MX host, for some
reson which I don't know, it didn't work, then the email
sent to our seconday MX host (which is our ISP mailhosts),
and It will quesed up there for 3 day, and finally we got the email.
I checked we didn't have any sendmail or network problem
at that time when the sender tried to send us email.
The sendmail daemon and network connection are all up all
My question is:
1. Under what conditions, the email will go to next MX host?
2. How long will it try the first MX host before it goes to second
3. If someone send an email to us from an unresolvable domain, our mailhost
will reject it cuase of MAIL FROM command, will it then go to next MX
4. Any ideas about my above problem?