Consider a situation where I'm logging in over SSH from machine A to machine B, I have an X session on machine A, and I want to run an X program on B.
ssh -X B makes this work transparently. But what if the server configuration lacks
X11Forwarding yes, I don't have root permissions on the server, and the server administrator is indifferent?
It's obviously possible to forward the X11 connection, since I can transfer whatever I want over the SSH channel. In fact, if the local X server allows TCP connections, it's as easy as
ssh -R 6010:localhost:6000 (to be adjusted for the display numbers). What about the common case where the local X server only allows socket connections? How do I do X forwarding conveniently and securely, with a minimum of installation requirements (especially on B)?