Why does a name server send no MX records?

[Mathias Koerber]

That really depends on whether an MX record is published in the DNS
your mailer queries. SOA replies are negative answers, with the status
telling you more about the error.

Example:
    If you query for:
        remoteserver.remotedomain MX

The nameserver will reply with

    ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 4
    ;; flags: qr aa rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0
    ;; QUERY SECTION:
    ;;      remoteserver.remotedomain, type = MX, class = IN

    ;; AUTHORITY SECTION:
    remotedomain.           1H IN SOA       ...

if remoteserver.remotedomain exists (maybe an A record etc), but that label
has no MX record
Note the status NOERROR !

It will reply with

    ;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 4
    ;; flags: qr aa rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0
    ;; QUERY SECTION:
    ;;      remoteserver.remotedomain , type = MX, class = IN

    ;; AUTHORITY SECTION:
    remotedomain.           1H IN SOA       ...

if there is not record remoteserver.remotedomain at all.
note the NXDOMAIN status.




-----Original Message-----
From: s.g.kamath at usa.net <s.g.kamath at usa.net>
Newsgroups: comp.protocols.dns.bind
To: comp-protocols-dns-bind at moderators.isc.org
<comp-protocols-dns-bind at moderators.isc.org>
Date: Tuesday, August 01, 2000 7:30 AM
Subject: Why does a name server send no MX records?


|
|There are some situations when a name server does not send MX records
|for an MX query and sends SOA records.   Is it supposed to be a rare
|case, or is it okay if happens often?
|
|Thanks
|
|