CentOS

Dear All,

I have some problem,

i have configure my mail server using postfix dan actually the mail server has run using sequiremaill.
But when i try using thunderbird or outlook express, i can't reach the server.

How can i solve this problem..
can sombody help me???

Is postfix/squirrel running (you can look for the socket in netstat -antp)?
Can you telnet from the client machine to the server?