Check Update, Update and Port Blocking

[Bill Wood <william.wood3@comcast.net>]

Do the protocols used for automatic check for updates and for updates
require specific ports to be available?  I recently switched my cable
modem to a Comcast Internet Gateway 1with the firewall set to high
security and subsequently a couple of update check icons appeared
indicating an error condition to to failure to access a file server.

I am currently running Debian 6.0.9 (Squeeze) stable.  I want to upgrade
to 7 but don't want to get hung up with bad downloads due to port
blocking by the firewall.

Thanks,

-- 
Bill Wood