If you are running a site with two or more hosts connected by a LAN, you will have to designate one host that handles your UUCP connection with the outside world. Between the hosts on your LAN, you will most probably want to exchange mail with SMTP over TCP/IP. Assume we're back at the Virtual Brewery again, and vstout is set up as the UUCP gateway.
In a networked environment, it is best to keep all user mailboxes on a single file system, which is NFS-mounted on all other hosts. This allows users to move from machine to machine, without having to move their mail around (or even worse, check some three or four machines for newly-arrived mail each morning). Therefore, you also want to make sender addresses independent from the machine the mail was written on. It is common practice to use the domain name all by itself in the sender address, instead of a hostname. Janet User, for example, would specify janet@vbrew.com instead of janet@vale.vbrew.com. We will explain below how to make the server recognize the domain name as a valid name for your site.
A different way of keeping all mailboxes on a central host is to use POP or IMAP. POP stands for Post Office Protocol and lets users access their mailboxes over a simple TCP/IP connection. IMAP, the Interactive Mail Access Protocol, is similar to POP, but more general. Both clients and servers for IMAP and POP have been ported to , and are available from sunsite.unc.edu below /pub/Linux/system/Network.