By default it looks like everything should pass until you set up some firewall rules:
tc@box:~$ sudo iptables -L -nv
Chain INPUT (policy ACCEPT 24731 packets, 36M bytes)
pkts bytes target prot opt in out source destination
Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
Chain OUTPUT (policy ACCEPT 13409 packets, 709K bytes)
pkts bytes target prot opt in out source destination
What do you get when you run the iptables command as above?