I prefer not to open a new thread related to the same how-to...
During my test I found out two troubles.
The first one is quota related: I set up a 10485760 default quota as described into the how-to, and all the testing users have got this quota. But I'm receiving lots of attachments that increase my inbox up to 18045000 and over...
What to check?
The second problem is Apache related. I didn't change anything of the original preferences but the ones asked in the how-to. I'm able to connect to Squirrelmail within the same subnet of the Ubuntu machine (192.168.10.x). I'm able to connect to Squirrelmail even from 192.168.1.x (the Ubuntu machine is into a DMZ). But I can connect neither to Squirrelmail nor Apache homepage from outside... even if I can reach all the other services (SMTP, POP3, IMAP4).
Thanks in advance!