I have been using a 3rd party Email Service Provider for around 5 years, which has let me have the same email address, reguardless of who my ISP has been. It was understood that the ESP would provide a pop3 server for you, but in order to send email, you needed to use your ISP's smtp server. My current ISP has stopped allowing this, and when I ran Windows I ran a personal SMTP server program. Now that I have switched to Linux, I am in the same boat again, of needing an a personal SMTP server so that I can once again send Email.

What do I need, and how do I set this up? Many thanks for any help.

Basically if u have an smtp server address that ur r already using to send mail u should be able to just fill in that address in your linux email program
eg.
smtp.anyone.com
it is the same protocol u r using to send mail regardless of os

Thats not the case. My EMP doesnt not provide its users with a SMTP server, they provide a pop3 server only (I guess the banner ads only make them enough to have a pop3 server, who knows). I needed to use my ISP's SMTP server, which they have stopped allowing relaying, so now I have to run my own SMTP server. I've set one up in Windows, but I dont know how to set one up in Linux. Hope the makes things more clear.

If u need an e-mail server for linux that will provide u with pop and smtp servers then u can check out this link
http://www.stalker.com/CommuniGatePro/#Current
or
http://www.emailman.com/unix/servers.html
Or do u have an addy for smtp server that ur using in windoze and u want to know how to assign the addy in linux?