Old School: Use Telnet to see if the ICA listener is working

Background

There are numerous ways to troubleshoot connectivity issues. As a consultant, the method is likely limited to what tools may be available to you when working from a machine, jump-box or thin client. In this case, it was a Windows 10 IOT thin client connected directly to a network, but the client does not have access to connect to anything within the client’s enterprise LAN.

The issue is a common one: Unable to connect to open a Citrix VDI session.

Troubleshooting Steps

The first step is to determine the remote VDA’s IP address. This is done by viewing the contents of the %TEMP%\*.ICA with the latest timestamp. Do not wait until the failure occurs because by default, the ICA file would be deleted when the process is complete.

Using the Windows’ built-in TELNET client, open a connection to the VDA’s IP address on the ICA port (1494)

If it’s unsuccessful, you would receive something similar to this:

Otherwise, you would get the “ICA” response:

Tip(s)

Though you cannot Telnet to the default Session Reliability port (2598) because it isn’t exactly “listening” on this port, you will still get something other than the normal “Could not open connection to the host, on port 2598: Connect failed”. The following error implies that there is a process associated to that port.