VPN connecting but doesn't validate password

[SybrCLocK]

hi, i`m having a stupid problem... i`ve setup vpn on 2 different networks:

1. internet ----> router (with 1723 forwarded) ----> PC (XP, with not firewall)
- i get the verifying username and password dialog box, but then after a timeout i get error 721 (the computer did not respond)


2. internet ----> Linux box (with 1723 forwarded and listening) ----> PC (XP, with no firewall)
- i get the same verifying username and password dialog box and the timeout.
here is a port query output to prove port 1723 is listening:
TCP port 1723 (pptp service): LISTENING
portqry.exe -n 84.x.x.x -e 1723 -p TCP exits with return code 0x00000000.

i tryed connecting from 1 to 2 and from 2 to 1.

- a Vista PC tryed as well and got error 806 (gre protocol 47), after timeing out at verifying username and password dialog box.


i dont get why the authentication is not working, it almost sounds to me like the authentication manager is not working or there might be a problem with encryption along the way, but i cant put my finger on it.


thanks

[su root]

In addition to TCP port 1723, you also need to allow protocol 47 (not port 47; protocol 47).

[Jon]

If the router supports GRE forwarding. My WRT54G v3 doesn't (although it will let it pass on occasion). I had to set my VPN server in a DMZ to get reliable connectivity. You may want to try the same if it your router can't pass it.

[SybrCLocK]

the router is a speedtouch 536

In addition to TCP port 1723, you also need to allow protocol 47 (not port 47; protocol 47).

i didnt get that when i saw some things i read... what do you mean by allowing a protocol...

thanks


- i`m also found out that XP only allows 1 client connected at one time... which i despise... i briefly looked for a reg hack/patch but didnt find any.
- i`m in the process to try open vpn on linux... i`ll see how well that works

[Jon]

the router is a speedtouch 536



i didnt get that when i saw some things i read... what do you mean by allowing a protocol...

thanks


- i`m also found out that XP only allows 1 client connected at one time... which i despise... i briefly looked for a reg hack/patch but didnt find any.
- i`m in the process to try open vpn on linux... i`ll see how well that works

Protocol 47 is GRE (generic route encapsulation) and is the encryption method used in transmitting the data over a PPTP VPN. If your router can't pass it, it's going to fail as soon as the session is requested (authentication data will be sent by GRE, which means the connection is made, but it won't authenticate, as in your situation).

You're going to have to look at your router's documentation and see if there is an option to enable protocol 47 (GRE passthrough). If there is not, you will need to place the computer acting as the VPN server within a DMZ so that GRE is not blocked. How to do that will also be in the documentation. If you have to use a DMZ, be advised that you are open to the Internet and a good software firewall will be necessary (or, at least, highly recommended).