be the old ipv6 problem.
As root, edit the file /etc/modules.conf
For now ignore the "Do not edit this file" warning.
You want a line in there which reads:
alias net-pf-10 off # IPv6
It may already be there but commented out with a #. If so uncomment it.
If this is the cause of the problem then it's because it takes a loooooooooong time to do a DNS lookup with ipv6 enabled (Don't ask me why, I don't know).
I think you will need to reboot to see the effect.