Am 18.07.2014 16:41, schrieb tejas sarade: >> You mean: no MX records; otherwise this is correct. > > Yes, that is what I meant. > > And I think that Postfix parameter ignore_mx_lookup_error controls the > behaviour when there is no response for MX lookup at all. > I guess that 'no MX' and 'no response for MX lookup' are handled differently
no MX by definition implies fallback to A record existing but empty MX implies config error at the receiver __________________________________ ignore_mx_lookup_error: "Ignore DNS MX lookups that produce no response" if there is *really NO response* and so defer is the only sane action no response means no answer and no NXDOMAIN so nobody knows the right hop and in that case fall back to A-record is stupid because in case of a network error or firewall dropping packages and a domain configured with an explicit MX which is not the A-record you would try to deliver to the wrong host and if there is a MTA but not acting as MX wrongly get "non existing address errors"
