PPTP going through, but L2TP is stopped?

Hi All,

I am configuring a VPN server, and in "front" it has a WatchGuard's Firebox
firewall and an ISP router.

I have a contact to the guy administering the Firebox, and he says that all
the ports are enabled:
UDP: 500, 1701, 4500
TCP: 1723
GRE, ESP, AH (IP Protocol 47,51,50)

The ISP's router should let everything pass through.

Now, when I connect using PPTP, everything works fine, but when using L2TP,
I get no acces (my client says that it disconnected because "the security
layer encountered a processing error during initial negotiations with the
remote computer").
Nothing can be seen in VPN server's log.

The Firebox guy says that he can see me in the Firebox's log when connecting
via PPTP, but nothing is registered when using L2TP.

Now, it is not my home connection, since I am using L2TP to connect to my
work.

Then it is at some point in between - is there a tool which I could use to
find where is that show-stopper?

Thanks in advance,

regards from Zoran

Also check the NAT in the client site if you have one. Or this troubleshooting may help,

L2TP/IPSec Troubleshooting
http://www.chicagotech.net/ipsec.htm

Bob Lin, MS-MVP, MCSE & CNE
Networking, Internet, Routing, VPN Troubleshooting on http://www.ChicagoTech.net
How to Setup Windows, Network, VPN & Remote Access on http://www.HowToNetworking.com
"Zoran" <(E-Mail Removed)> wrote in message news:975BAA82-D0D9-4186-B21F-(E-Mail Removed)...
Hi All,

I am configuring a VPN server, and in "front" it has a WatchGuard's Firebox
firewall and an ISP router.

I have a contact to the guy administering the Firebox, and he says that all
the ports are enabled:
UDP: 500, 1701, 4500
TCP: 1723
GRE, ESP, AH (IP Protocol 47,51,50)

The ISP's router should let everything pass through.

Now, when I connect using PPTP, everything works fine, but when using L2TP,
I get no acces (my client says that it disconnected because "the security
layer encountered a processing error during initial negotiations with the
remote computer").
Nothing can be seen in VPN server's log.

The Firebox guy says that he can see me in the Firebox's log when connecting
via PPTP, but nothing is registered when using L2TP.

Now, it is not my home connection, since I am using L2TP to connect to my
work.

Then it is at some point in between - is there a tool which I could use to
find where is that show-stopper?

Thanks in advance,

regards from Zoran