finding out more about reverse DNS and fixing it?

[Jim Reid]

>>>>> "LRW" == LRW  <deja at celticbear.com> writes:

    LRW> We send out monthly e-mails to our customers, and I've just
    LRW> noticed we get a few replies back from domains saying they're
    LRW> refusing e-mail from ourserver because we don't have a
    LRW> reverse DNS.

    LRW> Can someone point me to something that explains what a no
    LRW> reverse DNS error indicates and how to take care of it?

Reverse DNS maps IP addresses to hostnames. Every IP address that's in
use is supposed to have a reverse DNS entry which provides the name of
the host that's using that IP address. In your case there's no entry
for the system that's making the SMTP connections in the reverse DNS.
This is typically one of the characteristics of sites that send
spam. So some of the places you send mail to will refuse to talk to
you as they can't find from the DNS the hostname that corresponds to
the address that's connecting to them. Talk to your IT provider and
get them to fix it. If they can't/won't do this or if don't understand
what you're now telling them, find another one.