VPN error 721

[Allan]

For nearly 2 years I ran a VPN service on a Windows 2000
server. Without any changes to the server, the clients,
XP's, now stop at the "Verifying Username and
password..." and gives a 721 error.
I have looked over all the policies, and so on, and I
even installed a fresh copy of Windows Server 2003 on a
separate hard disk in the same computer, and there is the
same error.
I see in Network Monitor the intitial connection, and
then the request for authentication, and then a request
to drop the connection. I can log on locally as the VPN
user.
I have conntacted the ISP to see if they imposed any
filters, but they say as long as we have Internet
connectivity, that is all they are responsibile for.
I have checked the routher we use as well.
Thank you for any assistance.

 

[Sharoon Shetty K [MSFT]]

Error 721 is usually caused by the router (or some other router/firewall in
the path) blocking GRE.

 

[Guest]

Thank you for your reply. I opened the ports for GRE on our router, and I have not changed anything since then. Are there additional ports or something else that I should open up?
Thank you again.
Allan

 

[Sharoon Shetty K [MSFT]]

For PPTP VPN on the client machine 1723 TCP port needs to be opened. GRE is
not a port, its a IP protocol and the router/firewall should not block this
protocol for successful connection. Some routers call the GRE protocol as
PPTP passthrough.

--
Thanks,
Sharoon
---------------------------------------------------------
This posting is provided "AS IS" with no warranties, and confers no rights.

Thank you for your reply. I opened the ports for GRE on our router, and I

have not changed anything since then. Are there additional ports or
something else that I should open up?

 

[Guest]

Thank you for the reply. One of the tests I made was to try to connect a XP Pro client by using an ISP dial-up with no XP firewall. The XP computer was given a valid IP address out of the modem pool, and there was no router between the XP and the Internet. There was the same router on the VPN server side that had worked before. (In fact the connection to the client was so open that an Internet worm infected the XP client while I was running the tests.)
Today I also tried a Windows 2000 Pro client, and I get the exact same results that after "Authenticating..." there is error 721.
In the RAS log where I used to see the name of the account connecting with the VPN, there is just a blank between quotes.
I fully appreciated your help.
Allan

 

[Guest]

Thank you for the advice. My VPN server side routher, a D-Link 604 asks for a private/public port for the protocol type. For GRE I have 47/47 and it is open for TCP and UDP. The other protocol and ports that are open are 1723, 1701, 500 and 47.
One of the tests I preformed was to connect a XP Pro client to the Intermet by using a modem dial-up. The XP was assigned a valid IP address from the modem pool. There was no router between the XP client and the Internet, and the XP did not have the firewall turned on. I got the same delay with the "Authenticating..." and then the error 721. In fact the IP connection was so open that the XP client was infected by a worm during the tests.
Today I configured a Windows 2000 Pro as a VPN client, and the results were exactly the same.
Does Microsoft offer a test VPN server to test clients with?
I fully appreciate your advice.
Allan

 

[Guest]

Thank you for the advice. My VPN server side routher, a D-Link 604 asks for a private/public port for the protocol type. For GRE I have 47/47 and it is open for TCP and UDP. The other protocol and ports that are open are 1723, 1701, 500 and 47.
One of the tests I preformed was to connect a XP Pro client to the Intermet by using a modem dial-up. The XP was assigned a valid IP address from the modem pool. There was no router between the XP client and the Internet, and the XP did not have the firewall turned on. I got the same delay with the "Authenticating..." and then the error 721. In fact the IP connection was so open that the XP client was infected by a worm during the tests.
Today I configured a Windows 2000 Pro as a VPN client, and the results were exactly the same.
Does Microsoft offer a test VPN server to test clients with?
I fully appreciate your advice.
Allan

 

[Guest]

Thank you for the advice. My VPN server side routher, a D-Link 604 asks for a private/public port for the protocol type. For GRE I have 47/47 and it is open for TCP and UDP. The other protocol and ports that are open are 1723, 1701, 500 and 47.
One of the tests I preformed was to connect a XP Pro client to the Intermet by using a modem dial-up. The XP was assigned a valid IP address from the modem pool. There was no router between the XP client and the Internet, and the XP did not have the firewall turned on. I got the same delay with the "Authenticating..." and then the error 721. In fact the IP connection was so open that the XP client was infected by a worm during the tests.
Today I configured a Windows 2000 Pro as a VPN client, and the results were exactly the same.
Does Microsoft offer a test VPN server to test clients with?
I fully appreciate your advice.
Allan

 

[Guest]

Sorry about the repeats, but I kept on getting an error, and I didn't think my replies posted.
Allan