Citrix – Cannot connect to the Citrix XenApp server. Network issues are preventing your connection.

Been banging my head on this since yesterday.

Initially I tracked it down to the fact that I couldn’t ping my XenApp servers. Dummy error on my part – I had forgotten to set the default gateway in the DHCP scope. That didn’t help though, and even though I could ping the XenApp servers and connect to ports 1494 and 2598. Learnt how to enable Citrix Reciver logging but that didn’t give any errors either (go to HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Citrix\ICA Client\Engine\Configuration\Advanced\Modules\Logging for 64-bit OS, or HKEY_LOCAL_MACHINE\SOFTWARE\Citrix\ICA Client\Engine\Configuration\Advanced\Modules\Logging for 32-bit OS, specify a value for LogFile, and set everything to true). Googled a lot, read various forum posts, finally came across this blog post that suggested turning off the IE proxy settings. And that helped. Aaargh!

I had specifically tried via the Receiver application rather than IE just to avoid any gotchas like this. But my bad, the Receiver uses IE proxy settings it seems.

Update: So why was the proxy affecting my Citrix connections? For this the log file provided an answer.

When connecting to any of my resources, I noticed that the connection was being made via IP address using an HTTP request to port 1494:

This is because I was connecting to the StoreFront server directly and it was redirecting me to a resource.

In contrast, if I were using a NetScaler gateway, the same entries would look like this:

No IP address is involved there as the NetScalers do the needful via the STAs etc.

So all I had to do was add an exception for the IP range of the XenApp servers in my wpad.dat/ global.pac files to go DIRECT rather than via proxy.