Recently I have installed some Windows Updates on ISA 2006 server.
The installation finished ok, but a strange thing happened afterwards.
People started calling me saying that they can’t connect to VPN.
I’ve checked all the settings on the ISA server and made sure that all was OK.
After verifying that all the settings are correct, I tried what every windows admin does – I tried to remove all the settings, and reconfigure them from scratch.
Removing the VPN settings is pretty easy on ISA, so that took me no more than 5 minutes before I reconfigured all the settings from scratch.
Now that I was sure that all the VPN settings were reconfigured, I tried connecting to the VPN again – but nothing!
Now, I started thinking about other factors that could cause this to happen – and next factor is Routing and Remote Access.
In ISA server 2006 Routing and Remote Access is the one who is responsible for creating the PPTP tunnels for the users, and the one who manages the traffic.
I looked at the settings under Computer Management and found the problem – to my big amazement there were no PPTP ports available for users to connect.
That is a bit odd I thought since I remember allowing for 35 clients to connect to the VPN, which means I’m supposed to see 35 available ports here.
I’ve then tried what every windows admin tries and reinstalled Routing and Remote Access – but nothing, still I can’t see any ports available for connections.
After searching for a bit on the internet I finally came up with the solution.
Apparently, one of the Windows Updates (KB953230) that I installed causes the server to use the PPTP port (1723) for other causes.
I then found an article describing how this updates affects an ISA server:
Also on this Article I found the Solution for my problem.
I downloaded and installed the following ISA Update and that solved my issue:
If that update still doesn’t solve your issue, read thru the article and you will find a vbscript that disables the settings that KB953230 set’s.
Hope this information helps!