These days i m into a tricky problem and i m unable to solve it. The situation is that our mail server is situated outside the LAN (i mean its outside the company premises i.e. at a secure data center). I have enabled a port forwarded on my gateway (linux based gateway) which forwards the pop and smtp traffic to our mail server. Now consider that my domain name is example.com and my emailaddress is firstname.lastname@example.org if some one inside the lan sends an email to my email address it goes thru the smtp proxy to the mail server and then i can download that email thru the pop proxy (in our gateway), in this way the local email travels around the world. Now i want to deploy a local mail server at my company premises so that if some ones send a mail inside an organization it is stored at the local mail server and when some ones tries to download his emails some mails would be coming from local mail server and some will be coming from the outside mail server. If someone sends a mail to my mail address from outside the lan it should go to the real mail server. i think i have clearly metioned my situation if some one wants more details then i will be more than happy.