Postfix/Dovecot Hostname issues

[BackinBlack]

Here is yet another wall I have hit head first!

After fixing the errors with dovecot I was able to get it to connect from my webmail app.
however I cant send E-mail off the network or receive them from outside of the network ( IE Gmail,yahoo )

I have notice that for some off the wall reason my E-mail address from the local postfix is coming up like so ( Master@server.hsd1.md.comcast.net )
And not with my domain name.

Recently I notice that my domain name on my box is coming up as server@unknwon_domain Now I am not sure if that has anything to do with it
but I cant seem to set it to anything else.

Im really lost here if someone has any idea please fill me in!

Thanks all!