NoMachine NX - Support: Article


Added on:	2006-05-20

Last Modified:	2006-05-20

Applies to:	NX Technology

Why nxssh 2.0.0 needs to require the X11 forwarding when the connection is encrypted?
Starting from version 2.0.0-4, nxssh will request the X11 forwarding if the connection is encrypted. The X11 forwarding will not used by NX, and the forwarding will be still managed by nxserver. The problem is that if we don't request the X11 forwarding, SSHD will not consider the session interactive and will unilaterally turn on the Nagle algorithm on the remote socket, causing a visible slowdown.

As a consequence, the key added to the nx user on the NX server should not have the 'no-X11-forwarding' option set. If the option is set (for example when connecting to older NX servers) or if the X11 forwarding has been disabled by the system administrator, the NX connection will work unaffected, but the users will be unable to enjoy the best performance when running the session over the encrypted connection.

Please note that this is actually a SSHD problem and there is really little we can do to overcome it. The alternative would be to force the use of a tty and configure it in a way that it is transparent to the NX traffic. This is to be better investigated.