Launching firefox on remote server causes local firefox to open the page instead

By default, Firefox will talk to the existing Firefox process and reuse it.

If you wish to override this behavior and start a new process, add the -no-remote command line option when starting the second Firefox process:

firefox -no-remote

The -X switch forwards remote X clients to your local X server. Firefox must use some internal X Window system communication mechanism to detect that it's already running on your display and tell the already-running instance to open a new window.