a problem with X connection to HPC server-------local computer IP name

[dh]

I am trying to connect to a SGI Onyx 300  server from an PC with Win ME and
cygwin at home through typical

Xwin.exe -ac -query remote_ws -from <my local computer IP name >

but the remote login screen doesn't appear properly. It's just a blank
window.

I think my problem is really with local IP setting. I am not sure about my
local IP.
It is a 3 pcs LAN connectting to the internet through a router. My pc got a
local IP: 192.168.0.3, whist 3pcs share one external IP(as gateway) provided
by ISP.
But neither of the IPs can work(openning DISPLAY).

My problem is only with an XDMCP-query session.
What I must do to access a machine with SSH and "X -query" in this case?

Thanks in advance.
Philip D.