pptp error 721 (kb not helped)

[scott]

Hi,

PPTP connections appear to have stopped working (has been working for
2 years prior to sp4)

Reffering to KB 271731 (PPTP clinets cannot connect to a PPTP server......)

- i have 2 nic's, one is now removed
- i amended registy to include ValidateAddress on pptp adapters and set
DWORD to 0

One line in this article suggested the following:

"to resolve this issue, configure the firewall or the router so that the
source of the PPTP reply packets is the same IP address that the PPTP
clinets use"

I dont understand what this section is saying. How to i configure the SOURCE
of the PPTP reply (my vpn server) to be the same IP address that the clinets
use ?

MY SETUP
The router and firewall allows incoming PPTP ports 1723 and GRE
(protocol 47).

net
..
..
192.168.0.1
router
192.168.2.1
..
..
192.168.2.50
firewall
192.168.1.25
..
..
192.168.1.199
VPN server

PPTP and GRE are forwarded to appropriate port.

Thanks
Scott.

 

[Sharoon Shetty K [MSFT]]

Hi Scott,

What is the error you are getting?

Thanks,
Sharoon

 

[Sharoon Shetty K [MSFT]]

Sorry just realised the error is mentioned in the subject!

What is the OS on the VPN Server and the VPN clients?

Check these KB articles if they help -
271731 PPTP clients cannot connect to a PPTP server that has multiple IP
http://support.microsoft.com/?id=271731
and
810839 VPN Client Cannot Establish a Connection After You Install a Service
Pack
http://support.microsoft.com/?id=810839

Thanks,
Sharoon

 

[scott]

Hi,

Thanks for reply.

OS on server is 2000 advanced sp3 (rolled back from SP4)
OS on client is 2000 sp3 (new install after 2000 sp4 cause error 721)
Also get error 650 from win98se.

Unfortunetly i have allready attempted the fixes that both
http://support.microsoft.com/?id=271731 and
http://support.microsoft.com/?id=810839 suggested i.e regedit fix.

I have come in on Monday moring and PPTP is working again. The same thing
however happened last week and it stopped working again after a day.

Im just wondering if the symptoms i.e error 721 and 650 are a result of
another problem that starts and stops.

Thanks for any advice.
Scott.

 

[scott]

After a few hours win2k PPTP connection started getting 721 error.

Cant understand why it was working earlier ?

This is depressing.

Thanks
Scott.

 

[scott]

I noticed that when leaving it a couple of days it will connet again. As
soon as i disconnct and attempt connection again I get the 721 error.

Thanks
Scott.

 

[scott]

I tried restarting both machine, but still cant connect.

 

[scott]

i can connect internally from xpsp1 clinet to server.

sounds like a routing problem but why would it work the first time only ?

ports 1723 and gre correct.

 

[scott]

Got a better test:

NET
v
ROUTER
v
ROUTER > win2k clinet (WS012)
v
FIREWALL
v
RAS SERVER

- The win2k clinet (WS012) on the middle router (DMZ) can ALWAYS establish a
PPTP connection to RAS SERVER.
- This connection passes through the FIREWALL.
- Once this connection has been made all other external PPTP WIN2k clients
can connect.
- After WS012 disconnects and after several mins all external WIN2k that
attempt connection get error 721.

What the heck is going on ?

Thanks for any information at all.
Scott.

 

[scott]

futher testing showed:

win98 on external ip connect ok (firewall report PPTP 1723 + GRE)

win 98 manually disconet, reconnect (frewall report PPTP 1723 only)

Its like GRE was lost during the second connection. IE second time GRE did
not make it as far as the FIREWALL.

Im checking middle ROUTER.

 

[airwolf]

hey scott, my name is mariano, I have the same problem that you have.
I see that your last message is a little old but if you can read my
message I would like to know how you could fix the problem.

PD: if I try make a vpn conection from internal lan work, but when I
try to make a connection from outside I have the same problem like
you.


my e-mail is (e-mail address removed)

thanks for your help

Mariano Ortu.