Quiet X on Port 6000 TCP

Page 260 of the second edition of Hacking Linux Exposed gives a simple trick to prevent X from listening on port 6000. If you run the X Window System using 'startx' from the command prompt, and have nothing but sshd listening, you'll find port 6000 listening once X starts: 



netstat -natup



Active Internet connections (servers and established)

Proto Recv-Q Send-Q Local Address           Foreign Address         State

tcp        0      0 0.0.0.0:6000            0.0.0.0:*               LISTEN             

tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN


Instead launch the X server using 'startx -- -nolisten tcp'. Here's the netstat output now: 



Active Internet connections (servers and established)

Proto Recv-Q Send-Q Local Address           Foreign Address         State

tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN


Better yet, add the following to your .bash_profile to automate this process:


alias startx='startx -- -nolisten tcp'

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