We have over a hundred client sites making connections to our RDP server, and all but one are having no problems. The one may lose a connection to the server up to 3 or 4 times in 5 minutes - you will see the RDP client "reconnecting". Sometimes, the reconnecting will occur for 2 or 3 attempts before it's successful. All locations have independent Internet connections with various firewalls. The one location that is having a problem is using a Sonicwall TZ 105 firewall, and we've had two people look at this firewall to see if a problem can be found on that device. I don't know what firewall the other locations are using. A TCP timeout setting was increased from 15 minutes to a day. We didn't expect this to help, because we can have a lot of problems even in a 15 minute window, and it ended up not affecting anything. We've upgraded the firewall's firmware to the latest version.
We can't ping the RDP server from this location, but we have done a continuous ping to the last hop that is available, and there may be an occasional drop, but the total is a fraction of 1%. I know that having ICMP connectivity doesn't mean that TCP isn't having a problem, but the connection seems stable.
Does anyone have a thought as to what we might look at? Thanks