XP to 2k8 RDP Instant Disconnect - Any Ideas?

[Vimeous]

As usual using an RDP session from my Windows XP SP3 desktop to remote admin servers.
I can happily connect and admin a Windows Server 2008 SP1 VM on the LAN.

When I try to connect to its sister VM (similar config) at a remote site (same domain, different subnet, other machines on same subnet ok) the session connects and I get a brief view (sub 1 sec) of the server desktop only for it to abruptly terminate.

There are no error messages.
There are no Event log entries on either desktop or server.

Using VMware Infrastructure Client to view the VM it shows the server revert to the login screen when the rdp session fails.

I've been hunting for answers but have drawn a blank so far. Has anyone else seen this behaviour and been able to resolve it?

[Splash]

Not even a succesful/failed login in the logs?

Does this happen with all accounts, or just the one?

[Vimeous]

Nope not even that.

I'll try more accounts this afternoon.

[MaddAussie]

Are you trying to connect to the console or one of the TS sessions?

[smargh]

Classic signs of an incorrect MTU somewhere and/or packet fragmentation. RDP likes big packets.

You might find that if you reduce the "resolution", lower the bit depth, turn off the desktop background (i.e. the massive wallpaper on Dell servers) and any fancy RDP features, you might get more time to do stuff but as soon as you start dealing with large images then you might get disconnected.

Alternatively, as this a VM, disable all TCP and IP offloading features on the NIC in the guest OS, then the host OS if that doesn't help. The 2008 R2 and Win7 tcp chimney feature also causes problems sometimes - it's fine to do the netsh command on actively-used production servers, but it might take a few minutes to kick in.

[Vimeous]

Are you trying to connect to the console or one of the TS sessions?

TS. Can connect to it slowly for other remote functionality like registry/event logs etc.

Smargh how different is what I am doing to a typical XP to XP RDP session over the same hardware as those work fine.

[smargh]

Smargh how different is what I am doing to a typical XP to XP RDP session over the same hardware as those work fine.

From what I can tell in your original post, different NIC drivers are probably involved, and the switches/routers are different which might have incorrect MTUs. There are probably some other variables too, which I can't think of right now.

Disabling the offloading features won't break anything and is worth a try.

[Vimeous]

Classic signs of an incorrect MTU somewhere and/or packet fragmentation. RDP likes big packets.

You might find that if you reduce the "resolution", lower the bit depth, turn off the desktop background (i.e. the massive wallpaper on Dell servers) and any fancy RDP features, you might get more time to do stuff but as soon as you start dealing with large images then you might get disconnected.

Alternatively, as this a VM, disable all TCP and IP offloading features on the NIC in the guest OS, then the host OS if that doesn't help. The 2008 R2 and Win7 tcp chimney feature also causes problems sometimes - it's fine to do the netsh command on actively-used production servers, but it might take a few minutes to kick in.

I've other machines that take a while to load their RDP sessions because of background images so I understand that suggestion but that is very different to this situation.
In that case the session just starts slowly.
In this case it starts very quickly - everything appears on-screen (no images etc - nearly vanilla 2k8 install) - then the rdp session simply vanishes!

It's like a crash that leaves no trace.

I'd say more but I've got an idea I need to test and the engineers need all our PC's off a little while......

[smargh]

I've other machines that take a while to load their RDP sessions because of background images so I understand that suggestion but that is very different to this situation.
In that case the session just starts slowly.
In this case it starts very quickly - everything appears on-screen (no images etc - nearly vanilla 2k8 install) - then the rdp session simply vanishes!

I know. I have seen it before - it happens for me when I user an RDP gateway over a specific proxy. RDP sometimes requires large packets, especially during initial logon. Sometimes it doesn't require a large image and it happens instantly regardless - it depends. Crank down the resolution & fancy features to the bare minimum - do the symptoms change?

Disable offloading.

[Vimeous]

Fixed it.

It's a legacy hangover from when I was last using the VM.
I said both 2k8 VM's were similar but that reminded me that is no longer the case. In the last batch of testing we added the Terminal Server role to the off-site VM but didn't add any licenses. This is ok for the initial grace period but when this expired it closed off all TS connections - including the default admin TS as well.

That'll learn me I guess!


Thanks for the other suggestions

smargh this VM doesn't have offloading to disable in the guest OS but I'll keep in in mind if I see similar issues in the future.

[smargh]

Huh. Good to know - thanks

When I've seen licensing issues in the past there has always been at least a little indication in the event logs.