RE: X thro ssh

[Styma, Robert E (Robert)]

>  
>  Hi fellow admins,
>  
>  I posted to this fedora.desktop and was redirected.
>  
>  I have a peculiar requirement. We have two offices. People from second
>  office(say #2) want to connect to the server in first 
>  office(say #1). They
>  want to run the GUI applications in the office #1 server from 
>  office #2.
>  
>  I tried to do this with VNC server and it works fine. But VNC 
>  is goes thro
>  unencrypted(open) connection. Is there a way to do this in a secured
>  way(read that xdmcp is not possible as it uses UDP).
>  
>  Inside our network(LAN) if connect from one system to other 
>  thro ssh and
>  start an gui application that application shows up in the client. This
>  doesn't happen when i connect to server and start gui 
>  apps(says display not
>  set). iptables runs in the server. Do i have to open any port 
>  for that?
>  
>  Any help or pointer in this regard is appreciated.
>   
You can use port forwarding within SSH to accomplish this
task with VNC.  In a nutshell, you port forward some port near 5900
(the vnc port) on the local machine to port 5900 on the machine
running the vnc server.  This is done in your ~/.ssh/config file.
For example:
 LocalForward 5925 192.168.0.5:5900

You then run:
vncclient localhost:25
and it will connect through the secure tunnel to port 5900 on the
target machine.  In the example 192.168.0.5

For X, the task is even easier.  Run:
ssh -X -Y remote_machine.my.domain
(where remote_machine.my.domain is the other machine)
and X will be forwarded back to the local machine.
If this does not work, check the /etc/ssh/sshd_config to
make sure X11 tunnelling is allowed. (search for X11 in the file).

Bob Styma

X thro ssh

[Saravana Kumar]

STYMA, ROBERT E (ROBERT) wrote:

> > 
> > Hi fellow admins,
> > 
> > I posted to this fedora.desktop and was redirected.
> > 
> > I have a peculiar requirement. We have two offices. People from second
> > office(say #2) want to connect to the server in first
> > office(say #1). They
> > want to run the GUI applications in the office #1 server from
> > office #2.
> > 
> > I tried to do this with VNC server and it works fine. But VNC
> > is goes thro
> > unencrypted(open) connection. Is there a way to do this in a secured
> > way(read that xdmcp is not possible as it uses UDP).
> > 
> > Inside our network(LAN) if connect from one system to other
> > thro ssh and
> > start an gui application that application shows up in the client. This
> > doesn't happen when i connect to server and start gui
> > apps(says display not
> > set). iptables runs in the server. Do i have to open any port
> > for that?
> > 
> > Any help or pointer in this regard is appreciated.
> > 
>  You can use port forwarding within SSH to accomplish this
>  task with VNC.  In a nutshell, you port forward some port near 5900
>  (the vnc port) on the local machine to port 5900 on the machine
>  running the vnc server.  This is done in your ~/.ssh/config file.
>  For example:
>   LocalForward 5925 192.168.0.5:5900
>  
>  You then run:
>  vncclient localhost:25
>  and it will connect through the secure tunnel to port 5900 on the
>  target machine.  In the example 192.168.0.5
>  
>  For X, the task is even easier.  Run:
>  ssh -X -Y remote_machine.my.domain
>  (where remote_machine.my.domain is the other machine)
>  and X will be forwarded back to the local machine.
>  If this does not work, check the /etc/ssh/sshd_config to
>  make sure X11 tunnelling is allowed. (search for X11 in the file).
>  
>  Bob Styma
>   
Thanks For the help Bob.

Let me put on what i did from first. 

In the beginning(before posting here) i took two systems(rose & glob) to
test how this works. Both are FC4 systems and the default(X11Forward yes in
sshd_config) is unchanged. I connect from rose to glob thro ssh(ssh
rose.mydomain.com) and say xclock the app shows up in rose. But when i
connect from glob to rose thro ssh(ssh glob.mydomain.com) and say xclock it
wont work. This is annoying. Any idea where i am going wrong. As both are
inside lan there is no firewall in them. i can connect in text mode from
each other.

I am going to try what you said in a short while and post the results here.

Thanks Again,

regds,
SK

X thro ssh

[Saravana Kumar]

Saravana Kumar wrote:

>  STYMA, ROBERT E (ROBERT) wrote:
>  
> >> 
> >> Hi fellow admins,
> >> 
> >> I posted to this fedora.desktop and was redirected.
> >> 
> >> I have a peculiar requirement. We have two offices. People from second
> >> office(say #2) want to connect to the server in first
> >> office(say #1). They
> >> want to run the GUI applications in the office #1 server from
> >> office #2.
> >> 
> >> I tried to do this with VNC server and it works fine. But VNC
> >> is goes thro
> >> unencrypted(open) connection. Is there a way to do this in a secured
> >> way(read that xdmcp is not possible as it uses UDP).
> >> 
> >> Inside our network(LAN) if connect from one system to other
> >> thro ssh and
> >> start an gui application that application shows up in the client. This
> >> doesn't happen when i connect to server and start gui
> >> apps(says display not
> >> set). iptables runs in the server. Do i have to open any port
> >> for that?
> >> 
> >> Any help or pointer in this regard is appreciated.
> >> 
> > You can use port forwarding within SSH to accomplish this
> > task with VNC.  In a nutshell, you port forward some port near 5900
> > (the vnc port) on the local machine to port 5900 on the machine
> > running the vnc server.  This is done in your ~/.ssh/config file.
> > For example:
> >  LocalForward 5925 192.168.0.5:5900
> > 
> > You then run:
> > vncclient localhost:25
> > and it will connect through the secure tunnel to port 5900 on the
> > target machine.  In the example 192.168.0.5
> > 
> > For X, the task is even easier.  Run:
> > ssh -X -Y remote_machine.my.domain
> > (where remote_machine.my.domain is the other machine)
> > and X will be forwarded back to the local machine.
> > If this does not work, check the /etc/ssh/sshd_config to
> > make sure X11 tunnelling is allowed. (search for X11 in the file).
> > 
> > Bob Styma
> > 
>  Thanks For the help Bob.
>  
>  Let me put on what i did from first.
>  
>  In the beginning(before posting here) i took two systems(rose & glob) to
>  test how this works. Both are FC4 systems and the default(X11Forward yes
>  in sshd_config) is unchanged. I connect from rose to glob thro ssh(ssh
>  rose.mydomain.com) and say xclock the app shows up in rose. But when i
>  connect from glob to rose thro ssh(ssh glob.mydomain.com) and say xclock
>  it wont work. This is annoying. Any idea where i am going wrong. As both
>  are inside lan there is no firewall in them. i can connect in text mode
>  from each other.
>  
>  I am going to try what you said in a short while and post the results
>  here.
>  
>  Thanks Again,
>  
>  regds,
>  SK
>   
Sorry in glob ForwardX11 yes was not enabled in the ssh_config. Now
everything works fine from both systems. And hey it works without
specifying -X, -Y options.

Just to add up in both machines vncserver is not running.

regds,
SK