Remote Desktop

Kipton Moravec kip at
Mon Aug 16 14:52:47 UTC 2010

On Fri, 2010-08-06 at 16:56 -0500, Kipton Moravec wrote:
> On Fri, 2010-08-06 at 12:10 -0400, Patrick Doyle wrote:
> > On Fri, Aug 6, 2010 at 11:15 AM, Kipton Moravec <kip at> wrote:
> > > I am having problems with Remote Desktop running on a computer behind a
> > > firewall.
> > I presume you mean you want to connect to a Ubuntu (or other Linux
> > distro) server from a Ubuntu (or other Linux) client using VNC -- not
> > to a Microsoft Windows machine using Microsoft Remote Desktop.  If my
> > assumption is incorrect, then the rest of this response probably won't
> > help much.
> > 
> > >
> > > I have opened up port 5900 and pointed it to the IP address of the
> > > remote computer I want to connect to. Is it TCP or UDP?  I have tried
> > > both and can not get it to work.
> > VNC uses TCP
> > 
> > >
> > > Both computers are behind NAT Firewalls. If I want to initiate a remote
> > > desktop from my Home computer to the Remote Computer, I only have to
> > > have port 5900 open on the firewall to the remote computer.  It does not
> > > need to be opened on the firewall of the Home computer right?
> > right
> > 
> > >
> > > It does work on my home network where I do not have a firewall between
> > > the computers.  I am wondering if there are other ports it uses like
> > > telnet, SSH or FTP. I have those ports open and working, but the
> > > firewall has them on non-standard port numbers for the Internet side.
> > nope.  VNC just uses port 5900 (or 5901 if you connect to :1, 5902 for
> > :2, etc...)
> > 
> > If you configure your home firewall to route port 5900 to port 5900 on
> > the destination computer, then you should be able to point your VNC
> > client (i.e. Ubuntu remote desktop connection) to the IP address of
> > your firewall and it should just work.
> > 
> > It should even just work if you do that from within your home network,
> > although that depends a little on the firewall.
> > 
> > Do you know the IP address of your firewall?  Not the
> > address, but the address it was assigned by your ISP.
> > 
> > That's the address to which you should be connecting from the outside.
> > 
> > --wpd
> > 
> Thanks. That is what I thought it was doing. I have the computer setting
> a dynmic dns address and I can get in using ssh. (So yes I know the
> address.) But to reconfigure the ATT 2WIRE router I need to be on the
> LAN side to log in and it is a web browser interface. Unfortunately the
> location of the remote computer is not easy to access, so it is hard to
> get in and out for testing. 
> Kip

I think I figured out the problem, but do not know how to fix it.

Recoup the problem:

I have a Xubuntu computer at a remote site behind a NAT Router to the
Internet. I directed TCP port 5900 on the Router to point to the Xubuntu
Computer port 5900.

I tried to access from my home computer using remote desktop on Ubuntu
08.04 LTS and could not get it. I have a dynamic DNS set up and can
access the computer with ssh so the IP address is O.K.


Last Friday I went out there to check on another problem we were having
on a different computer and ran vino-preferences on the computer. The
window was different than the System->Preferences->Remote Desktop on
Ubuntu 08.04.

In regular Ubuntu I have a check under the Advanced tab that says "Only
use Local Connections". In Xubuntu I do not have the option, and it says
local connections only. 

Am I screwed? Do I have to load 08.04 on that computer to get a remote
desktop that is not local, or is there a config file somewhere that I
can manually edit? Or is there a different vino-preferences I can get?

I put Xubuntu on it because it was an old computer (566 MHz) with not a
lot of RAM (384 MB), but the program running uses less than 10% of the
resources. And it is the only thing running until I log in. I have to
have a window system because the router has a web based interface that
is only accessible from the LAN side and I would like to remote desk top
in, and then configure the router.  


Kipton Moravec AE5IB .- . ..... .. -...

"Always do right; this will gratify some people and astonish the rest."
--Mark Twain

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