Sorry about asking my question again. This time I try really hard
to explain the case. I thought my question was trivial, and the
answer too. (It must be).
I run a mail relay for an ISP.
A customer says: "Can we use your mail relay as a secondary MX?"
I say: "Okay, just give me at list of the domain names we should
accept mail for".
I put this list into control/rcpthosts on mail.isp.dk (name not real)
and get mail.isp.dk added as a lower precedence MX in my customer's
zone files. That should be enough, right? Nothing more necessary.
The problem.
I have, too many times, seen mail.isp.dk reject mail to
my customers domains with the following error:
"Sorry. Although I'm listed as a best-preference MX or A for that host, "
"it isn't in my control/locals file, so I don't treat it as local. (#5.4.6)"
The error message above contains two statements:
My customers domain names are not in control/locals. That is true.
Our mail relay is listed as the best-preference MX. That is wrong.
I cannot imagine that DNS can claim our mail server to be the best
MX for our costomer's domain, which it is not, and never has been.
DNS says (made up names):
customer.dk. <--- customer's zone
IN MX 10 mail.customer.dk. <-- customer's server
IN MX 20 mail.isp.dk. <--- Our server
To "fix" the reject problem I always make entries for my customers
domains into control/smtproutes, pointing to their best preference
MX host. It works, but I can't believe that hardcoding the best
MX is the way to do it.
Testing is difficult because I can only send mail from our networks,
so rcpthosts is never consulted. Testing from outside is possible
using telnet, but I don't have a shell account on the outside.
--
Med venlig hilsen / Regards
Netdriftgruppen / Network Management Group
UNI-C
Tlf./Phone +45 35 87 89 41 Mail: UNI-C
Fax. +45 35 87 89 90 Bygning 304
E-mail: [EMAIL PROTECTED] DK-2800 Lyngby
