The tab lists custom firewall settings added to the firewall profile. The Add, Edit and Remove controls can be used to amend the settings in the list.

These settings are mergeable. Changes to these settings do not require a reboot of the system.

Example Custom Firewall Records

Dropping NetBIOS searches on an ISPs DNS

We suggest that the following filter is always added to the firewall facing the Internet to avoid costly but otherwise typically pointless requests from Windows machines making DNS searches on the DNS server at your ISP.

• Direction: Drop

• IP Protocol: 6 (TCP)

• Match Offset: 20

• Match Length: 4

• Match Data: 00890035

• Match Mask: FFFFFFFF

Browsing Non-Standard Port Numbers

The radio button for HTTP permits ports 80 and 443 through the firewall. Some hosts use non-standard ports for HTTP traffic, for example 8080, 8000, 8001, 8002, etc. You can add individual filters for these ports as you find them.

You wish to access a web page but you cannot because it uses TCP port 8000 instead of the more usual port 80, use the entry below.

• Direction: Out

• IP Protocol: 6 (TCP)

• Match Offset: 22

• Match Length: 2

• Match Data: 1F40

• Match Mask: FFFF

A more general additional entry given below allows all TCP ports out.

• Direction: Out

• IP Protocol: 6 (TCP)

• Match Offset: 0

• Match Length: 0

• Match Data: 00000000000000000000000000000000

• Match Mask: 00000000000000000000000000000000

Routing All Internet Traffic through a WinProxy

If you wish to put WinProxy in front of all Internet traffic via the Control Unit. The following firewall allows only the WinProxy server to contact the Internet : -

1. Create a new Firewall profile and select Drop for all protocols

2. Under Custom create a new Firewall Entry

3. In Notes enter the name of the server allowed. Then use the default settings except in Local IP Address enter the IP address of the WinProxy Server, in Local IP Mask enter 255.255.255.255 and in Direction select Both Directions.

Stopping PINGs

You wish to stop pings - this is ICMP Filtering. Using the data below can create a firewall filter that performs the following; Trap Pings; Trap Ping Replies; Trap Both.

• Trap Pings: Protocol = 1, offset = 20, data = 08, mask = FF

• Trap Ping Replies: Protocol = 1, offset = 20, data = 00, mask = FF

• Trap Both: Protocol = 1, offset = 20, data = 00, mask = F7, Traps Both.