RDP Services Extremely slow - time outs - etc

Description

Ever since making changes to network configurations in your environments in order to secure them against the Struts 2 vulnerability, you may find that RDP sessions no longer work properly when initiated from within the N-able N-central N-able RMM site. ( The sessions fail, or they are unstable, or they time out , etc )

Environment

• N-able N-central, all versions.

Solution

The problem isn't caused by patching or upgrading N-able N-central. Many partners have chosen to lock down port 22 in an effort to limit the potential for an attack vector on that port.

If your envionment is setup to allow traffic to port 22 from only the N-able N-central support center, the RDP functionality will be effectively crippled.

To re-establish full RDP functionality, you will need to create firewall rules allowing connections to happen from all customer networks. By allowing the WAN IP of your customer locations, the SSH tunnel will be able to complete its connection and RDP will work as intended.

The reason this happens is because the RDP applet in N-able N-central makes use of an SSH session between the N-able N-central server and the end-point device. SSH is invoked for establishing an RDP tunnel, which will not work if the port is blocked.