RDP Reconnecting on Win2k8 R2


I’ve got an issue with a newly installed Window 2008 R2 Remote Desktop Server.  While RDP’d in, frequently at random intervals the connection is interrupted, “Reconnecting.  The connection has been lost. Attempting to reconnect to your session…”  That will tick to the 3rd or 4th connection and then reconnect.  

This is a guest on a 3 host (Dell R510) Citrix XenServer 5.6 FP1 Pool with HA (Equalogic 4000 iscsi SAN).  Each host has a bonded LAN connected to redundant Dell PC 6224 switches.

To troubleshoot so far:

-I’ve confirmed this will happen over LAN or WAN, from windows 7 or XP
-run netsh interface tcp set global autotuning=disabled on both the workstation and server
-Verfied Xentools are installed and up to date for the version of Xen it’s running; reinstalled xentools
-Disabled all offload options on the NIC driver.  Since it’s a guest, there is no “allow power off” option
-Migrated the guest to another host in the pool; no other machines have connection issues
-run a continuous ping to the server while connected, nothing is dropped although the interval may not be quick enough.
-VNC’d into it, with a concurrent RDP connection.  Both are dropped at the same time.

The last note makes me think that it’s something at the network level, but it’s contradictory that it would only effect this one guest.  Any thoughts on what to check next?

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Patmac951Connect With a Mentor Commented:

That's a head scratcher.  Have you tried another port on the switch?  I have had some strange thinks like this happen in the past and replacing the cable/or cable ends both at the NIC and Switch ends and trying another port has solved it.
Lee_YCPConnect With a Mentor Commented:
Can you use wireshark to see which end is dropping the connection?
This looks like a hardware problem, since both connections are dropped at the same time.
I would follow both Patmac and Lee's advices.
The fastest "test" would be replacing the cables and see if that solves anything.
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dsteph3Author Commented:
Thanks for the quick response!  I'm not onsite again until Wednesday, but I'll try the new cable/ports then. Come to think of it, I'm not sure both switches would have a connection to the rest of the network (which would be a big whoops on my part!).  We're in the process of migrating the old physical network to the new Xen pool so it's a bit of a mess right now. So it could be the bond dropping the connection when the 2nd physical NIC tries to communicate.  Although I can't imagine how I wouldn't have a bunch of other connection issues.  They're main application is up and live on the Xen pool with 120 people connecting to it.  Although it doesn't exactly "stream" as RDP does.

Lee,  I'm downloading wireshark now and will post back.
dsteph3Author Commented:
Ok- so I swapped out the cables for the LAN interface on the Xen host the server is currently running on and plugged them into different ports.  I also verfired that both switches are connected up to the rest of the LAN.  I'm still getting the dropped connection.

I also ran wireshark from both sides of the RDP connection.  The client shows TCP Retransmissions at the time of the drop, while the server does not.  I tried this on two different clients and came back with the same result.  

The only thing done differently with this server than the other ones in this pool is that it was export/imported in from another stand alone Xenserver, that wasn't part of this pool yet.  I thought maybe it didn't like the LAN interface change in the process, so I removed and readded it, but still having issues.  Maybe something was corrupted during the import?
I have this problem on physical and virtual Windows 2008 servers. I have found the following links moderately useful. I am still looking for a better solution. I have the problem locally and over WAN connections.


dsteph3Author Commented:
Hi kevinhseih.  Thanks for the suggestion.  I tried out the keep alive an it actually made the issue worse.  The connection is dropping now, and doesn't allow for a reconnect right away.  In some cases, it's another 2 minutes before I can reconnect.  

At this point, I haven't configured any user accounts on the server yet.  I think I'm just going to start with a new guest install.  At least then I can elimiate a corrupted imported image as the problem and then we're most likely back to an issue at the network level.  I'll post back with the results on Monday.
dsteph3Connect With a Mentor Author Commented:
Wow- so I just figured out the issue.... Embarrassed to say it was an IP Address conflict with an unrelated switch.  I came across it when I brought up the replacement guest with the same IP and was still having the same issue.  I had a continuous ping going and was shocked to see that when I downed the server it was still responding!  Not sure how it happened.  Admittedly our network documentation needs updating and there isn't a whole lot of organization by range in the current subnet.  Things are kind of a mess until we decom about a rack full of infrastructure.

dsteph3Author Commented:
Solutions were close to the issue (e.g. physical network related)
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