On 6/21/2013 10:24 AM, Titanus Eramius wrote: > Hello > > I've searched several times about information on the PTR record, and > what myhostname in main.cf should be. The problem is not the > information, but the fact that I struggle to understand it...
Ideally, the PTR, A record, and HELO hostname should all agree. > > This server runs with the IP address 46.21.105.38 from a hosted VPS, and > using dig to do a reverse lookup gives > 46-21-105-38-static.serverhotell.net. There doesn't appear to be a matching A record for that PTR, so the setup is incomplete. Postfix will label such a host as "unknown". Most sites (but not all!) will still accept your mail. Best to request your hosting company to give you a custom PTR with your domain name, something like smtp.example.com, mx1.example.com, mail.example.com, etc. so your server looks like a mail server and not a random infected bot. If this host handles several domains, just pick one for the PTR and A record. No need to list them all. Whatever PTR you end up with, there should be a matching A record with the server address. > > Does this means I should use 46-21-105-38-static as myhostname? While technically correct to use the 46-21-105-38-static.serverhotell.net hostname, that's the same name a random infected bot will use and should be avoided. I would still suggest a myhostname setting that makes you look like a mail server instead of a random bot, even if it doesn't match the PTR. Make sure you also have an A record set for the hostname that points back to your server's IP. -- Noel Jones
