Moving mail directories to new machine

[Joe Clever]

I am migrating my personal email server from Redhat 7.0 to a new
machine running White Box Enterprise Linux 3.0. I want to move my mail
directories from /home/username/mail on one machine to the same
locations on the new machine via my network. I tried using scp but it
failed with an error saying that mail was not a normal directory.
These servers are on two different LAN segments with a firewall/router
between them. I am fairly new to Linux, so any specific advice would
be helpful.

Thanks