Security updates and apt-get

["Michele Della Marina" <dellamarina@gmail.com>]

Hello!
I use a stable ditribution on my servers, and periodically I make
apt-get update and apt-get upgrade using security.debian.org in
sources.list
I think (as I know) that this operation updates the critical packages
installed in my systems.

If I add a line in sources.list like ftp.debian.org/debian stable main
etc etc, and I make apt-get update apt-get upgrade, how my packages
are updated? Can I upgrade my system using both repository?  ... sorry
for my bed english, I hope my doubt is clear enough.


--
Michele Della Marina
michele@cdm-soft.it