Outbound RDP session from XP SP3 fails, but port 3389 is reachable

Question

I can telnet 192.168.10.10 3389 and get a connection. But RDP client to 192.168.10.10 immedietly bails (less than 1 sec) "connect" button greys briefly, RDP app remains on screen. Have tried these from other nodes on the subnet to 192.168.10.10 with same result.

On 192.168.10.10 Allow Remote Desktop is enabled. On 192.168.10.10 windows firemall is off. I'm connecting from the same subnet, i.e no firewall hardware / routers in the way. AV software is installed but other nodes on same subnet allow RDP connection using exact same AV settings (network group profile) Checked 192.168.10.10 for any additonal AV software or local firewall products. I'm sure none exist. Checked registry to ensure 3389 was the port set for listening.

Seems to be an XP problem (SP3). 2 nodes on the my LAN have this issue, but many others work fine.

Solution 1

I've been having this same issue as well.

Port 3389 will be open and accessible via Telnet. When I try to log in it'll seem to have connected but the session disconnects after a brief pause (about a second or two).

After hunting around on the web and reviewing my system logs I discovered that it was caused by a problem in the display drivers. In my case it was caused by the ATI Catalyst drivers but systems with nVidia drivers have been known to suffer the issue as well.

I'd suggest reviewing your Event Log > System for messages such as:

\SystemRoot\System32\RDPDD.dll failed to load

In my case the issue was resolved by rolling back to the basic ATI video driver.

Here's a more in-depth discussion of the issue. http://blogs.technet.com/b/brad_rutkowski/archive/2008/01/04/systemroot-system32-rdpdd-dll-failed-to-load.aspx

Solution 2

Using Telnet you open a connection to the port. Using an RDP client that's only the very first stage. It then goes on to negotiate some connection parameters and perform authentication. A fail on any of those and it immediately disconnects.

There may well be an issue on the RDP host but Telnet is absolutely useless for diagnosing such a problem beyond verifying that the port can be connected to. I'd be more inclined to use Wireshark, or similar, to watch what happens when the RDP client tries to connect.

Comments

[joeqwerty]

What OS is running on 192.168.10.10?

[redknight]

from what ip are you initiating the rdp connection?

[Philip]

I'll bet it's a 2008R2 TS, we've had XP-SP3 machines do the same thing, never figured out why. We're in the process of upgrading everything to Windows 7, which has never had the problem.

[joeqwerty]

RDP uses TCP, not UDP.

[LapTop006]

Can also confirm RDP does not require UDP at all, I've got a few hosts behind a NAT, and only TCP 3389 is forwarded.

[Sam]

I stand corrected then. Can't really remember what happened in my situation anymore - maybe the audio streaming option is selected, and because UDP wasn't open, RDP failed to connect?

[Philip]

If you're blocking UDP, audio just wont work correctly. It does not drop the entire connection. The newest video features also use UDP (or maybe it was RTSP, my memory is a bit fuzzy).

[pablo]

had the same issue and this fixed it.