Postfix Email Delivery Problem

[sedat1903]

Hi to all,
I have configured the postfix, this was my first postfix configuration, and I have a US robotics modem, I redirect the 25 port to the my email server, it can send email, but it cant recive email, I edited the dns configuration on hosting company, gave the ip as Us robotics modem, when I wirte nslookup in command line, my domain's email server Ip adress shows this US robotics IP, and when I try to connect to IP adress the robotics modem dredirected to my email server, but mailserver doesnt accept, when I send an email from hotmail or yahoo, it responses hours later , says that, "we couldnt delivver the email, the email was in queue very log time, I wont try again"
what can be the problem, what I should add to main.cf to take the emails from quee, I couldnt figure out the problem, any suggestions

thank you all

[till]

Please ask your DSL / Cable provider if they block port 25.

[jasonralston]

mydestination = needs to be your FQDN.

Hope this helps