RDP freezing when using VPN SSL forticlient

[ESA]

Hello

we're facing a problem we can't solve. Fortinet support and Microsoft support also break their teeth on it.

We have a Fortigate 81E, firmware6.2.4. Our users connect in SSL VPN with a Forticlient. This allows them to connect in RDP to different VM servers of the company. They do, however, have problems with frozen displays. If they don't work on the server in RDP, after a while they freeze, and after a few seconds (between 5 and 30 sec) the connection comes back.

A continuous ping test shows that there is no packet loss. The Forticlients have been upgraded, and the MTU of our WAN connection is 1500. And for Microsoft nothing to report on the HyperV side. Finally, no problem found when testing in VPN SSL web mode.

Do you have any idea where this might be coming from?

Thank you for your help

Ed

[prowl65]

If you make any policy changes, have any automatic route changes (i.e. IP SLA, IPSEC Site to Site, routing protocols) etc... you will find RDP sessions (and Outlook RPC) will drop.  RDP will normally reconnect by itself but I find Outlook hangs and requires a restart of outlook.  This I believe is related to sessions being marked as Dirty when realistically they shouldn't be, i.e. a BUG

Won't confirm this is your issue, just know we are experiencing this, and hoping 6.2.5 will resolve.

[brycemd]

It may not be your exact issue, in fact it more lines up with Prowl65's issue, but 6.0.10 fixes a lot of SSL VPN issues, including:

RDP sessions are terminated (disconnect) unexpectedly