Re: XDMCP through a firewall w/ nat

[Alexander Gottwald <alexander dot gottwald at s1999 dot tu-chemnitz dot de>]

On Fri, 5 Mar 2004, Robert Mecklenburg wrote:

> I'm trying to connect to a linux machine with kdm and I'm having
> trouble.  My configurations are:
> 
> linux:
> Mandrake 9.2
> KDE
> ssh configured with X11Forwarding
> 
> Windows XP:
> ICF disabled
> Latest Cygwin X (updated daily)
> 
> Linksys Firewall/gateway/hub
> 
> - I've successfully configured kdm for remote access and tested it
>   from a cygwin host on the linux local lan.
> 
> - I've correctly configured ssh (I don't think this matters) and can
>   connect from the windows machine through the firewall to the remote
>   host and can use ssh -X successfully.  I realize this isn't exact
>   relevant, but you never know what someone will ask about.
> 
> - The firewall is doing nat (I don't know if this is what all
>   firewalls do), so I have a linksys_ip and a windows_ip.
> 
> - I've configured my local firewall to pass ports 6000-6020 through
>   to my windows host.
> 
> - I've tried these configurations unsuccessfully.  With these
>   I get no error, but no login window.
> 
>   XWin -query $remote_ip
>   XWin -query $remote_ip -from $windows_ip
>   XWin -query $remote_ip -clipboard -from $windows_ip
> 
> 
>   With these I get the same error:
> 
>   XWin -query $remote_ip -from $linksys_ip
>   XWin -query $remote_ip -clipboard -from $linksys_ip
>   XWin -query $remote_ip -fp tcp/$remote_ip:7100 -clipboard -from $linksys_ip

You can only use from with a local address. 

>   XWin -query $remote_ip -fp tcp/$remote_ip:7100 -clipboard -from $windows_ip
> 
>   Could not init font path element tcp/207.88.121.38:7100, removing from list!
>   Fatal server error:
>   could not open default font 'fixed'
> 
> 
>   I could be I'm not running a font server on port 7100, or that the
>   port is inaccessible for some reason.

You can try with ping 207.88.121.38 if the host is reachable.

> I've read many of the posting in the archives and the faq.  The faq
> says none of this will work through a firewall, but maybe it's out
> of date.  I've noticed other posting from people who may have gotten
> this to work?  Or have I misread them?

With the firewall I suggest using X11Forwarding.

ssh -o "X11ForwardingTrusted yes" -X linuxhost

You can then start a remote session with startkde or similar.

bye
	ago@linuxtag
-- 
 Alexander.Gottwald@s1999.tu-chemnitz.de 
 http://www.gotti.org           ICQ: 126018723
 Chemnitzer Linux-Tag 2004 - 6. und 7. März 2004
 http://www.tu-chemnitz.de/linux/tag