Watchguard Firebox 2 (PPTP and GRE Pass Through)

Have a question or want to start a discussion? Post it! No Registration Necessary.  Now with pictures!

Threaded View

Heres the issue

Windows 2003 Server (Small Business Server)
Default Gateway:


Watchguard Firebox 2
System Manager 7.0
Trusted Interface:
External Interface:
Optional Interface: Not Configured

What we are trying to do is create a VPN connection to the Windows
2003 server from a remote VPN client. To create this we have done the

New Policy

Inbound - Any
Outbound - Any

NAT: -

When i complete this the remote VPN client stays on the verifying
username and password process.

When connecting up a spare firewall that we have Watchguard SOHO 6 we
are able to receive pptp traffic but when using the Watchguard
2 this doesnt work.

Looking at the traffic monitor i can see that the firewall is
reporting a GRE error.

To resolve this issue i used the PPTP rule that is already available
in the list of policies that are able to be created. When doing this
have noticed that the NAT option is disabled. To sort this we have
tried to create a 1 - 1 NAT using another IP address out of your IP

Any ideas would be great

Re: Watchguard Firebox 2 (PPTP and GRE Pass Through)
On Mar 20, 6:28 pm, wrote:
Quoted text here. Click to load it

I've seen this with a Firebox X Edge. The rule is there for PPTP
forwarding through to the 2003 RRAS server but it just doesn't work.
The client disconnects immediately and the Watchguard logs report
packets on 1723 being dropped. After extensive searching on the web
this seems to be a random problem that crops up with certain
combinations of NAT devices. In my case I am going through an ISA 2004
on my side, then through the Watchguard Firebox X Edge on the other
and this double-NAT combination doesn't work.

I can successfully pass PPTP through my ISA + many other devices
(including other Watchguards), and if I PPTP through JUST the
Watchguard (bypassing my ISA), that also works.

In all my research on this it seems the only solution is to change the
NAT device at either your end or the other end...


Re: Watchguard Firebox 2 (PPTP and GRE Pass Through)
On Thu, 29 Mar 2007 04:36:20 -0700, wrote:

Quoted text here. Click to load it

Why would anyone want to PPTP to the server when the firebox 2 acts as a
VPN (pptp or ipsec) endpoint and provides all that is needed without
having to expose the server itself. I never setup the servers as VPN
endpoints, only the firewall, which lets US control who reaches the server
and what ports they can use to reach the server.

Even the Firebox II device has PPTP pre-defined rules that can be added,
and yes, some cheap NAT routers don't properly pass GRE.

Leythos (remove 999 for proper email address)

Site Timeline