Problem to send email out of my Local LAN

I have ispconfig in centos 4.4, and in my local lan, work perfect I can send emal, but if i configure account out of site (not in my local lan), I cant configure account in outlook or any program, but I can use the web page to access (Squirrelmail). But a need to configure outlook and always send this error. "Outlook could not connect to the server SMTP, error (0x80042109)".

Help me!!!!....

 

You must configure your router to forward the ports 25 (SMTP) and 110 (POP3) to your mail server.

 

I have modem SPeedStream and port forwarding TCP 110 to 192.168.0.6, TCP 25 to 192.168.0.6, this ip is my server in LAN

 

Please make sure that your ISP doesn't block port 25.