Reverse DNS PTR
ERROR: None of your mail server(s) seem to have reverse DNS (PTR) entries (I didn't get any responses for them). RFC1912 2.1 says you should have a reverse DNS for all your mail servers. It is strongly urged that you have them, as many mailservers will not accept mail from mailservers with no reverse DNS entry.
it seems to be important as, if i'm not wrong, some (many?) providers won't be able to receive email from that servers.
i suppose that's not so true 'cause i've never had provider with ptr setted rightly but i have always sent my emails
