Hi,
from my workplace we use a proxy to connect to the outside world, including external ssh servers.
The problem is that the server is seeing the connection coming from the proxy and knows nothing about the client behind it. The ssh connection itself works fine, but x-forwarding does not work as expected. In my opinion this is because the server is trying to use the display of the proxy and not the one of the client.
Same issue with remote port forwarding, when someone uses the remote port I think the ssh server forwards the request to the proxy and not to the real client.

I have found two workarounds to solve the x-forwarding issue:
-create a VPN between the client and the server, and do the x-forwarding inside the VPN (which is similar to a LAN)
-install a VNC server on the ssh server, a VNC client on the ssh client and do a local port forwarding, then connect to localhost:xxxx

I'm sure the VPN solution will fix the remote forwarding as well, but... is there a way to get around these issues without using other software, maybe some kind of environment variables to set in OpenSSH?
Thanks.