Often referred to as an e-mail server, a device and/or 
program that routes an e-mail to the correct destination. 
Mail relays are typically used within local networks to 
transmit e-mails among local users. 

(For example, all of the student and faculty e-mail of a 
college campus.) Mail relays are particularly useful in e-
mail aliasing where multiple e-mail addresses are used but 
the mail relay forwards all messages to the specified e-
mail addresses to one single address. 

A mail relay is different than an open relay, where an e-
mail server processes a mail message that that neither 
originates or ends with a user that is within the server’s 
local domain (i.e., local IP range). 

Mail relay Softwares:
1.NoticeWare Email Server 4.3
2. Flash Mailer 20.