ISPs say my mail server is failing rDNSbut lookups indicated that is works?

Question

I have a mail server that has ~30 IPs attached to it. If I do a rDNS lookup it comes back to a FQDN and that FQDN resolves back to that ip. What are some reasons ISPs would fail. Could my system be technically correct though not follow best practices?

(I know this is a big question and difficult to answer without the IPs and Domains in question)

Answer 1

If the rDNS which is the REVERSE dns is not working then you have to go one level up from your machine (whoever supplies the line) and have them make a reverse entry in their system so that your forward DNS matches the reverse dns entry. (unless they assigned the block to you it wont match unless they made a block reverse entry and many don't.)
See this article
http://www.tech-faq.com/reverse-dns.shtml
And I quote.
"When you register a domain name with a domain registrar, you usually become responsible for that Forward DNS domain. In DNS terms, the domain is delegated to you.

However, you are not also responsible for your reverse records. Your Reverse DNS records are still most likely to be the responsibility of your hosting facility or ISP.

To make changed to your Reverse DNS PTR records, you must contact the company where you get your IP addresses from, usually a hosting facility or an ISP.

Alternatively, your ISP or hosting company may delegate a range of IP addresses to you, in which case you must configure Reverse DNS and PTR records in your DNS server."


My best help came from http://dnsstuff.com (the dns report) for a whole lot of help with this type issue. I had one which I just simply didn't even notice.
and found it there in a matter of minutes. Took sending that to my upstream provider to get them to understand the issue!!!!!

Answer 2

If you are using multiple IP addresses for the mail server, you are creating problems. Better to use one address and virtual domains from that. If you are using dynamic dns, this is very unreliable for mail service. Is it giving a true FQ domain name to other servers. If so are ALL the mx records for the domains pointing to it.

Answer 3

i did no longer have a situation beginning my mail, yet my sister has been having issues of all of it of this night. i've got observed a situation answering questions nonetheless, it takes a minimal of three tries to get the variety up for answering and lower back for posting. Gremlins. My sister puzzled if it became only her mail there became a situation with, as a results of fact she suggested a definite seek engine in certainly one of her solutions.