You're having firewall problems, eh?
You're at a client's, at work, or in a hotel that has restrictive firewalling rules. Perhaps you find yourself unable to use IRC.
IRC
Our IRC server listens on both ports irc://irc.codehaus.org:6667 and irc://irc.codehaus.org:7776. Additionally, an HTTP-based client is available at http://irc.codehaus.org/
SSH
If you can't ssh out of your location, you can also attempt to connect on port 443, which will generally get through as it masquerades as HTTP-over-SSL traffic, which proxies can't touch.
If you wanna do a CVS checkout, I found that the following script worked (save as ssh443)
#!/bin/sh ssh -p 443 $*
Then do
export CVS_RSH=ssh443
and perform your CVS checkout as normal and it works.
Adjusting repositories
Of course, Subversion and CVS maintain information about the repository you'd checked out before arriving at the restrictive location. You can convince Subversion to use a different port with an existing workspace by setting an environment variable.
set SVN_SSH=plink -P 443
SMTP
Your ISP perchance blocks SMTP traffic on port 25 to curb spam. If you're a hausmate, you can perform SMTP-auth against port 2525. Use your Codehaus username and password. If you don't have a password, make a sacrifice to a despot and ask nicely.