> Date: Thursday, October 26, 2017 12:36:37 -0700 > From: cac...@quantum-equities.com > > On 10/26/2017 12:21 PM, cac...@quantum-equities.com wrote: >>> the whole fact that mail was SENT by thunderbird has nothing to do >>> with the >>> fact that you need mail server on quantum-equities.com if you >>> want to RECEIVE mail for quantum-equities.com. >>> >>> configure postfix on quantum-equities.com that will have >>> "quantum-equities.com" in mydestination. >>> >>> or >>> >>> configure different MX for quantum-equities.com pointing to other >>> server that will receive mail for that domain >> >> The server which postfix is running on will be primarily for >> qualtum-equities if I ever get it running. But for the time being >> I've set myhostname = mail.delphi-real-estate.com and mydomain = >> delphi-real-estate.com . >> >> Also I've modified my zone file to this: >> >> delphi-real-estate.com. 28800 A 72.251.232.102 >> www 28800 CNAME >> delphi-real-estate.com. @ >> 28800 MX 10 mail.delphi-real-estate.com. mail >> 28800 A >> 72.251.232.102 mail.delphi-real-estate.com. TXT "v=spf1 mx a >> ip4:72.251.232.102/32" 102.232.251.72.in-addr.arpa. 28800 IN PTR >> mail.delphi-real-estate.com. >> >> Unfortunately though, my registrar removes IN from my PTR record >> automatically, and then fails me with "Syntax error". >> >> And sent mail still never arrives. No comments in maillog. > > Just as well, since PTR records are 1:1 to the IP. And I'll have 3 > domains on this server so I can't use PTR. > > Anyway, ARPA has not assigned this IP directly to me; it came > with my cloud instance. > > I'll set SPF and DKIM. >
There's no requirement that a mail server be in the same domain as the domain it's serving mail for. Many receiving mail servers will reject connections from sending servers where the reverse and forward dns entries don't match, and even more likely if the sending server doesn't have a PTR record. If you can't get past the HELO, it doesn't much matter if you have SPF and/or DKIM. You need to talk with your hosting provider to get them, or the people upstream from them if they don't control the netblock, to get the PTR record put in. Without it you will run into unreliable mail delivery issues.
