In article <mailman.302.1497854956.702.bind-us...@lists.isc.org> you write: >>* IP with *one* PTR >>* the A-Record for the PTR matches >>* smtp_helo_name of your MTA matches the same name > >Even this is not required. In fact, requiring this breaks SMTP RFC. >The only requirement on helo name is that host must exist and be canonical, >which means it has to point to A or AAAA record.
Regardless of what the RFC says, if an IP doesn't have matching forward/backward DNS that is an extremely strong indication that it's a random computer in a botnet and few people will accept mail from it. As others have noted, it doesn't matter what the forward/backward name is so long as at least one pair of A and PTR match. You do want the HELO name to resolve correctly, again, again non-resolving HELO is a very strong indication of a bot. Yes, we know the SMTP specs say otherwise but they haven't been updated since bot spam became such a problem. R's, John _______________________________________________ Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users
