On 09/09/2013 09:27 PM, Wietse Venema wrote:
Postfix does a hard bounce when the DNS server replies that the name has no MX record AND the DNS server replies that the name has no A record, AND (if Postfix IPv6 support is on) the DNS server replies that the name has no AAAA record.
Does that mean that postfix will do a hard bounce if there is no reply to an MX query after a timeout ? I thought it would at least try the other queries (A and/or AAAA) before giving up, since this costs no more than when there /is/ a (negative) reply.
Since postfix may be talking to a cache or a resolver with numerous hops in between postfix and the authoritative source, any of the queries may fail individually, and yet not be conclusive.
Postfix does a soft bounce when any of those lookups does not produce a reply.
This seems to suggest the former, but I am double-checking. -- J.
