unable to communicate with smtp server

Dear all

I am trying to configure sendmail, and made the initial changes, and enabled all the necessary deomns. i am telneting pop3 and smtp services. able to communicate with pop3 and i couldn’t communicate with smtp.
my sendmail is running and accepting connections. but still i couldn’t communicate with my smtp server. i didn’t enabled any firewalls, how to check my smtp port 25 is blocked? where i have to proceed… pls. help me as soon as possible. I stuck up here……