Help: Port Forwarding Rules
 
Introduction Enter your port forwarding rules here. You need to enter the following for each rule:
  • Rule Number: This defines where the rule is entered into the list. For example, to enter a new rule between 100 and 200, number it "150". The rules will be re-numbered on each iteration of the firewall, so you can continue entering rules between each new pair of rules. If you leave this blank then the rule will go at the end of the rule set.
  • Protocol: Select a network protocol, udp or tcp.
  • From: Where the forwarding is starting from (where the packet is originally sent to by the source).
  • From Port: What port the forwarding is starting from (what port the packet was originally sent to).
  • Destination: Select a destination network object (where the packet is to be forwarded to).
  • Destination Port: Select a destination network port (what port the packet is to be forwarded to).
Note that the From Port and Destination Port must both use the same protocol. You cannot port forward a TCP connection to a UDP port.
What is
Port Forwarding?
Port Forwarding is the reverse of IP masquerading. Masquerading works for all connections going out to the internet from a machine that is "hidden" on a network behind the firewall.

Port Forwarding allows connections in to a masqueraded machine, from the internet.

You need to have masquerading turned on for a network object in order for port forwarding to that network object to work.


Example
Rules
Here are some quick example rules that you might like to use. The rules are specified in the following format:
  • Protocol From From Port Destination Destination Port

  1. Forwarding packets to a mail server, where ETH0 is your firewall's internet address:
    • tcp ETH0 smtp MAILSERVER smtp
  2. Forwarding packets from your ETH1 address to a web server called WEBSERVER:
    • tcp ETH1 www WEBSERVER www

Tricks and
Traps
There are no functions to renumber, copy, or move a rule in this system. Some ways around this include:
  • To copy a rule: Click on the "Edit" icon, and change the rule number. For example, to make a copy of rule 3100, edit it, and change the rule number field in the edit window to 3150. When this is saved it will appear as a new rule.
  • To move or renumber a rule: Copy the rule to the new location, then delete the old rule.
  • To delete a bunch of rules: Click the delete button multiple times. How lazy can you get?