Hi,
I have configured email using MySQL, Postfix and Dovecot based on https://library.linode.com/email/postfi ... 0.19-mysql on Ubuntu 12.04 LTS
Further I've added Squirrel Mail for Email Client.
I can send mail to Email address on any domain and that works perfectly fine.

However, I can receive only internal mails. If I try to send mail from email id on some other domain like Gmail, I get following error:

"Google tried to deliver your message, but it was rejected by the server for the recipient domain by smtp.secureserver.net.

The error that the other server returned was:
550 #5.1.0 Address rejected."

It would be great if someone with more knowledge and experience could guide me here.
Thanks in advance.

"it was rejected by the server for the recipient domain by smtp.secureserver.net." - This means that your domain's MX record still points to godaddy mail servers. Change your domains MX record to point to the hostname of your linode, wait a few hrs and you should be able to get emails at your linode.

Thanks a lot! It took me some time to figure out the required changes in MX records in godaddy DNS configuration.
Earlier I set it to mail.mydomain.com
Just changed it to mail.mydomain.com. (a . in the end) and its working perfectly fine now.