|Debian Bug 623284
Openssl can lose track of it's certs. You can verify the problem has struck your system by running (as a normal user):
openssl s_client -CApath /etc/ssl/certs/ -connect chat.freenode.net:7000
You should see a load of output and then the connection will time out after a little while (under a minute). However it may tell you that the verification of the certificate has failed in which case you should be able to fix the problem by running the following command as root:
As you might guess from the example command to test with, the problem was initially spotted breaking connections to irc using ssl (with irssi at least) but it is likely to impact other software if it has struck your system.