port 25 disabled?

[Joe M Mar]

I am using Exim and I am able to send messages but not able to receive 
them. I can telnet to port 25 locally but I can't from a remote 
computer.  I think this is the problem as to why I am unable to recieve 
email.  I wonder how i can enable this.  Documentation only relates to 
enabling smtp on inetd but it is alredy enabled...
Please help..