The other day I posted a tip on how to enable the Network Access Protection client on XP SP3.  The client is also built into Vista (RTM and SP1) and is a little easier to configure.  Although the same command line from the XP SP3 config can be used, there is a MMC console as well.

Again before we configure the client we must set the Network Access Protection Agent service to start automatically, then start it.

Then we can launch the MMC console with the following command

napclcfg.msc

Once this opens up click on Enforcement Clients and then simply right-click the agent you wish to use and choose enable!

If you are a command line junkie or wish to script this you can also run the following command:

netsh nap client set enforcement ID = "#####" Admin = "ENABLE"

Just replace the ###### with the enforcement ID.  One last hint, you can see the enforcement ID circled as well if you forget and need to enable the client using Netsh.