If I'm in the office on the LAN, I can successfully connect to my Solaris 10 server via cygwin/x, by simply doing:
XWin.exe -query x.x.x.x
However, when I'm at home connected via VPN, if I do the same thing, I get a blank X display come up and then after about 10 seconds it dies with:
Fatal server error:
XDMCP fatal error: Session failed Session 8 failed for display x.x.x.x:0: Cannot open display
where x.x.x.x is my VPN address.
I then tried to connect via an ssh with X11 forwarding, but couldn't find a combination that worked.