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Class I Port Forward

Some more information on Port Forwarding (Virtual Servers)

This information specifically refers to the Conexant based routers – e.g. ASR8000, ASR8100, ASR8400 / SAMR-4110, SAMR-4114, AWR7210, AWR7214 / SWAMR-5110, SWAMR-5114 etc


Say we want to forward (in other words OPEN) some ports – 2090 and 2091 to our PC. There are two kinds of port TCP and UDP – TCP is the default type and so we normally use TCP unless we are told to use UDP.

The PC is on the IP address of in this example. This is how we would do it:

ID Public Port – Start Public Port – End Private Port Port Type Host IP Address
1 2090 2090 2090 TCP
2 2091 2091 2091 TCP

The ‘public start’, ‘public end’ and ‘private’ port are the same – this is very important.

You need to enter each port of a range separately otherwise it won’t work. That means if you want to forward 1001 to 1005 you need 5 virtual servers. There is normally a limit of 20 ‘virtual severs’ which obviously this means you cannot forward a range like 8000 to 9000 or whatever.

The older firmwares are a bit thick with ranges so if you put in a range like your example: public start = 6891, public end = 6900, private = 6891 then it would try to do this:

6891->6891, 6892->6891, 6893->6891 etc

It tries to point all public ports from 6891 to 6900 towards 6891 which probably isn’t what you want.


With a newer firmware you can enter a range that works correctly.

So in our example we could do just this:

ID Public Port – Start Public Port – End Private Port Port Type Host IP Address
1 2090 2091 2090 TCP

Only one line is needed for a range – the ‘public end’ port can be anything higher than the ‘public start’ port. The new firmwares are intelligent enough to understand the range means that it will forward 2090->2090 and 2091->2091.

Last updated by Neo on Saturday, August 29th, 2009
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