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Cannot access external XP RDP via ISA 2004 SP1 - 19.Apr.2005 1:23:00 PM

rralston

Posts: 18
Joined: 22.Jul.2002
From: Boston, MA
Status: offline

ISA 2004 SP1 on W2K3 (no SP).

When I attempt to access an XPSP2 remote desktop via ISA, the initial connection is made, but the login screen never appears, and then terminates with a "network error".

I have no problem accessing external W2K3 Terminal Services on standard RDP port 3389 or on alternate ports.

I can access this same XP machine via RDP if I bypass ISA. Firewall logs are no help as they only indicate initiated connection and closed connection. No helpful event logs on target machine, either. I *thought* I had tested this on ISA before SP1 months ago without any problem.

I also created an "all outbound" test rule to see if it would help me troubleshoot, but it changed nothing. Also, it does not matter if the client machine is XPSP2 or W2K3, they both have the same problem connecting to the target XP machine.

Maybe this is an ISA SP1 problem. Any ideas would be appreciated.

Thanks,

Rob Ralston

Post #: 1

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RE: Cannot access external XP RDP via ISA 2004 SP1 - 20.Apr.2005 11:33:00 AM

tshinder

Posts: 50013
Joined: 10.Jan.2001
From: Texas
Status: offline

Hi Rob,

Couple of guesses:

1. MTU issue (esp if DSL is on either side)

2. You need to start the RDP client in console mode

HTH,
Tom

(in reply to rralston)

Post #: 2

RE: Cannot access external XP RDP via ISA 2004 SP1 - 20.Apr.2005 12:19:00 PM

rralston

Posts: 18
Joined: 22.Jul.2002
From: Boston, MA
Status: offline

Hi Tom,

Thanks for a quick reply.

1) While I have SDSL on my end I don't believe that is related (I'll explain below).

2) I tried the console connection, but it did not help. From my understanding WinXP, like Win2K, doesn't recognize the /console switch.

More info:

1) If I put an XPSP2 on my SDSL router, behind a hardware fw appliance with proper port forwarding (essentially simulating a remote internet machine) I still cannot connect to it via ISA 2004 SP1.

2) The same XPSP2 machine as in 1, while connected to the same fw appliance (bypassing ISA) is able to connect to another remote XPSP2 machine via RDP (i.e., eliminate ISA and it works).

3) I tested this connection using another network behind an ISA 2000 SP2 machine, also connected via an SDSL router, and it works OK. (i.e., a WinXP client behind an ISA 2000 SP2 fw can connect to the same WinXP SP2 machine via RDP that I *cannot* connect to while behind an ISA 2004 SP1 fw)

If anyone is able to duplicate this problem to confirm it is not just my configuration, I would go to MS PSS with the problem to get it resolved.

Thanks,

Rob Ralston

(in reply to rralston)

Post #: 3

RE: Cannot access external XP RDP via ISA 2004 SP1 - 23.Apr.2005 1:31:00 PM

rralston

Posts: 18
Joined: 22.Jul.2002
From: Boston, MA
Status: offline

In my last post I asked if anyone can duplicate the problem. What I should have asked is if anyone has the above scenario working.

ISA Server 2004 SP1 on W2K3 (no SP)
Access Rule allowing RDP port 3389 or an alternate port.
XPSP2 client behind ISA
XPSP2 machine on WAN/Internet (could be located on WAN router for test, just so all packets go through ISA)
Attempt RDP from behind ISA to XP machine on WAN.

Obviously the remote XP machine must have Remote Desktop enabled, etc.

I only get to initial connection. Never get to login screen.

Thanks for any feedback.

Rob

(in reply to rralston)

Post #: 4