Received wisdom has been that all outgoing ports, other than those actually required for use (e.g. for DNS, the web, e-mail, newsgroups and possibly some others) should be closed.
However, I find it difficult to believe that any serious bug wanting to report home would try to use any port other than one of those which is almost certain to be open, and therefore I wonder how important it now is to close all unused outgoing ports.
I have always followed that practice (using IPCop) but I have found it rather annoying when I want to use ftp. For example, I have found using FillZilla that one needs to open 30 or so consecutive ports in order to use passive ftp.
My question is not entirely academic because circumstances may force me to use a firewall which does not have the ability to close outgoing ports.
Kind regards to all