Question : Tip: Full RRAS, NAT, IP routing etc. is actually available in Windows XP, W2K Pro etc.

This post is about the potentials hidden in non-server products such as Windows XP, W2K Professional etc.

Having looked around the site, I have seen many posts involving discussions of the Routing and Remote Access Service, Network Address Translation, IP routing etc. in Windows XP and W2K Professional.
Contrary to what the majority of the posts claim, the full RRAS service including all features such as IP routing and NAT is actually available in Windows XP, W2K Professional etc., not just in Windows 2000 Server products. The only thing that is missing is the appropriate GUI components to configure these options. Under Windows 2000 Server to configure these features one would usually use the Routing and Remote Access Service snap-in in Microsoft Management Console, usually available via the Administrative Tools in Start Menu. This feature is missing in Windows XP etc.

However! The features are actually there and fully working. To use them, one must use command line configuration tools, specifically "netsh".
Anything that can be configure on W2K Server using the GUI interface can also be configured in say Windows XP using appropriate commands given in netsh.

Here is an actual example scenario where I have successfully made use of this feature:

I had a machine A, running Windows XP Pro, which had access to the Internet via its single network card. I wanted to enable other computers to dial into A via a modem say (or in my particular case direct-cable connection) and thereby gain access to the Internet. It is pretty obvious that NAT is needed to make this possible, but Internet Connection Sharing is inadequate in this particular case.
The problem with Internet Connection Sharing on Windows XP is two-fold:
1) It only recognises computers connected to it via a network card as being on the private network, so those connecting in through dial-up, direct-cable etc.  (ie. RAS) can not form part of the private network.
2) As a consequence of 1), ICS is not willing to turn on (the check-box is missing) if you try to enable it using your sole network card as the Internet connection (public interface), since it expects that card to be the private interface.

To get to a solution, what I did was to not make use of ICS at all, but to pretend that machine A is in fact a Windows 2000 Server.
Under W2K Server, one would do this: enable NAT as one of the routing protocols in RRAS, add the network card as the public interface, and add
the dial-in connection as the private interface.
So I did exactly this on machine A with Windows XP, except I used netsh commands to configure the above options. I ussed commands in this order:

- netsh                      [to get to the netsh console]
- routing ip nat          [to switch to the nat context]
- install                      [to install NAT as one of the routing protocols]
- add interface "Local Area Connection" full              [enabling network card as public interface]
- add interface Internal private                                 [enabling dial-in interface as private interface]

After this, everything worked wonderfully. Another machine was connecting to A via a parallel cable, and has gained full access to the Internet.
Two minor comments:
- the name "Internal" is given in Windows products to the virtual interface representing the RAS
- in case you get an error message after issuing the "install" command, it's because you have ICS enabled on one or more of your interfaces (network card, dial-up connection etc.)
RRAS NAT and ICS are not compatible with each other, you can only use one or the other.

I suspect that similar things hold for IP routing as well. One should be able to configure it using netsh commands just like in W2K Server.

So what do you people think of all this? Comments are very welcome.
I think I have discovered a very handy and convenient feature here, that all the treasures of Server products are available in other Windows versions too.

You are welcome to ask me questions if something was unclear in the post above.

Answer : Tip: Full RRAS, NAT, IP routing etc. is actually available in Windows XP, W2K Pro etc.

PAQed - no points refunded (of 125)

modulo
Community Support Moderator