Here's a decent iptables for a workstation that doesn't normally serve hosted applications. It is meant to just block the network while allowing the user to still use the network unhindered. If services will need to connect to your system then you'll have to open ports in the firewall.
Code:
#load firewall config with iptables-restore < iptables.rules
*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
#The following rules required
...
