How to open a port?

Waleed Harbi waleed.harbi at
Wed Jun 14 05:11:44 UTC 2006

you must run xhost+ command and export $DISPLAY="ip:0.0" variable also this
option must like this DisallowTCP=true, if you have nmap it will show you
which ports opens nmap -sT hostname

On 6/14/06, Cameron Hutchison <camh at> wrote:
> Daniel Carrera wrote:
> >There are no iptable rules on either the server or my laptop. So it
> >looks like I'm barking up the wrong tree. I'm trying to open a remote X
> >connection and it isn't working, but it looks like the problem not with
> >a closed port. :(
> That depends on your terminology. If an iptables rule was in place
> blocking a connection to a port, I would call that a "blocked port". A
> "closed port" would be a port on which there is no service running. This
> is how ubuntu achieves a default setup with no "open ports" (or all
> "closed ports") - no services running on external interfaces. It does
> not use iptables to block ports.
> In your particular case (remote X connections), you need to have the
> X server run a service on a port. By default, it does not do this (in
> pretty much any modern distro) for security reasons. The X protocol is
> not particularly secure.
> The usual way to have remote X clients is to tunnel through ssh. If
> you ssh from a shell that can connect to an X server (ie. the DISPLAY
> variable is set appropriately and it has appropriate permissions to
> access the $HOME/.Xauthority file), you can use the -X argument to ssh(1)
> to enable X11 forwarding. Check the manpage for more details.
> If you still really want to enable external X connections, you'll
> need to configure your X server to listen on inet ports, and not just
> a unix domain socket. If you are running GNOME, look under "System ->
> Administration -> Login Window" on the "Security" tab. There is a checkbox
> labelled "Deny TCP conections to Xserver" which is checked by default.
> I've never used this checkbox so I cannot say 100% that it will run
> the X server with/without the "-nolisten tcp" X argument, but it's the
> sensible place for it. You'll need to log out and maybe even restart gdm
> ("sudo /etc/init.d/gdm restart" from a console shell) to have this option
> be applied.
> You can check the option has been applied by looking at the ps(1) listing
> for X ("ps auxww|grep X") and see if it has the "-nolisten tcp" command
> line argument. If it has, you will not be able to remotely connect to
> the X server.
> --
> ubuntu-users mailing list
> ubuntu-users at

:.Best Regards
Open Source Open Education
Waleed Harbi ,KSA
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