problem with smtp and pop3

[ayush1440]

hello frends ..
i just installed fedora core 6 and configure DNS,APACHE,and POSTfix server. my mail server is running quite good. now i have 2 configure all user mail to their outlook express software and it configured now .. but my problem is i have 2 write ip address at smtp and pop3 server name. if i write pop3.mydomain.com and smtp.mydomain.com then its not connect but if i write server ip then its connected and working fully. So i what should i do for writing smtp.mydomain.com and pop3.mydomain.com?

and another problem is for apache webserver. when i open my site through ip addresss then its open and when i write site www.mysite.com then its not open. So can u tell me whts the problem for this. \?

[athlon_crazy]

it's domain issue I think. nslookup / dig your domain from any client just to make sure it can be resolved!