Keyserver is used for storing and distributing OpenGPG keys. The Ubuntu project also maintains its own keyserver ( http://keyserver.ubuntu.com ) for distributing public-key to users.
keyserver uses HKP Keyserver protocol which listens on port 11371
Here’s how to enable the keyserver port on iptables:
[bash]
iptables -A OUTPUT -p tcp -d <key server ip> –dport 11371 -j ACCEPT
[/bash]