On 6/7/2013 7:46 AM, Nikolas Kallis wrote: > Hello, > > > > Before I had my ISP setup my IP address's PTR record to resolve to > one of my domains, my IP address resolved to > '123-243-137-139.static.tpgi.com.au'. If I had used > '[123.243.137.139]' as the host name of my mail server, would a > Postfix-based e-mail server enforcing > 'reject_non_fqdn_helo_hostname' accept my mail, or would the PTR > record have to resolve to '123.243.137.139' exactly (not > '123-243-137-138.static.tpgi.com.au')? > > There is allot I don't know about DNS. Does anyone know if a PTR > record can be set to resolve to an IP address? > > > - Thanks > > > > Regards, > > Nikolas Kallis
Generally only internal systems and spammers use IP literals for the HELO hostname. I wouldn't recommend it. I would suggest not using "123-243-137-139.static.tpgi.com.au" as your HELO, since that's what all the spam bots do. Some folks will reject such "generic" HELO names, or mark your mail as spam. You should use a HELO that makes you look like a mail server, such as 'mail.example.com' which has a matching A record pointing to your IP address. Then have your ISP change your PTR to match the "mail.example.com" you use as the HELO name. If not possible, some folks may still reject your mail. -- Noel Jones
