mail server problem

[awnlionel]

Hi,
I m trying to setup the mail server on whm with cpanelX but for some reasons i can send email outsite of the site but cannot get any reply to it, i use WHM for name server and such as well as dyndns.org for that if i telnet the domain name with 25 or 110 it will time out on the old server it was working fine but cannot find what the problem is, thanks for your help

[nickb]

Check and validate dns records for your domain...MX, A etc....get help from mail trouble shooter and dnsstuff.com to check errors in dns and mail routing.

[awnlionel]

Ok what do you mean by validate? dont get this one i did look at dnsstuff.com and the PTR was missing, any other suggestions?