Re: Remote open X application

Re: Remote open X application

[Harold L Hunt II]

Welson,

Welson Sun wrote:
> OK, I know what's wrong now. The step should be:
> 1. Start Cygwin X
> 2. xhost + Remote Server

No.  xhost is not needed, nor desired, when using ssh.

> 3. ssh -X Remote Server
> 
> This works for me now. At least the "refused by server" is resolved.
> 
> But not all Linux machines................
> 
> I can start X applications on some Linux machine in this way, but on some
> others, it still complains about:
> Error: Cann't open display: localhost:0.0

It is more likely that some of your Linux machines don't have ssh setup 
to allow X11 tunnelling.

Follow the instructions on the following page for ssh, very carefully:

http://xfree86.cygwin.com/docs/ug/using-remote-apps.html

You should not have any trouble if you do it this way... unless your 
Linux machines need to have their sshd configuration changed, which you 
can find documentation about elsewhere.

Harold

RE: Remote open X application

[Welson Sun]

Thanks Harold.

At first, I just followed the link you provided, but got the error as stated
in my previous email. Then I add the "xhost + ... " command before doing
ssh, and it worked for my Linux machines.

So, I think it might be that other Linux machines are not correctly set up,
especially for X tunnelling. I am not expert on this, I need to talk with my
system administrator. 

-----Original Message-----
From: cygwin-xfree-owner@cygwin.com [mailto:cygwin-xfree-owner@cygwin.com]
On Behalf Of Harold L Hunt II
Sent: Wednesday, December 17, 2003 8:03 PM
To: cygwin-xfree@cygwin.com
Subject: Re: Remote open X application

Welson,

Welson Sun wrote:
> OK, I know what's wrong now. The step should be:
> 1. Start Cygwin X
> 2. xhost + Remote Server

No.  xhost is not needed, nor desired, when using ssh.

> 3. ssh -X Remote Server
> 
> This works for me now. At least the "refused by server" is resolved.
> 
> But not all Linux machines................
> 
> I can start X applications on some Linux machine in this way, but on 
> some others, it still complains about:
> Error: Cann't open display: localhost:0.0

It is more likely that some of your Linux machines don't have ssh setup to
allow X11 tunnelling.

Follow the instructions on the following page for ssh, very carefully:

http://xfree86.cygwin.com/docs/ug/using-remote-apps.html

You should not have any trouble if you do it this way... unless your Linux
machines need to have their sshd configuration changed, which you can find
documentation about elsewhere.

Harold

RE: Remote open X application

[Welson Sun]

OK, with Harold's help, it now works for me at last.

By default, you should not need to set the DISPLAY variable, the sshd X11
tunnelling configuration should take care of this. But because some admin is
not familiar with this, you may need to set up manually.

Then I set it to be: localhost:10.1 and it works. But according to Harold,
if somebody else is logged on via ssh already and using 10.0, I should set
it be to 11.1, but I cannot know that.

Anyway, this is a problem with the Remote Linux machine's sshd X11
tunnelling configuration.

-----Original Message-----
From: Harold L Hunt II [mailto:huntharo@msu.edu] 
Sent: Wednesday, December 17, 2003 9:17 PM
To: Welson Sun
Subject: Re: Remote open X application

Welson,

Let's keep this discussion on the mailing list for others to see.

Welson Sun wrote:

> Hi Harold,
> 
> I am sorry that I don't use IRC, but I use MSN (welson_sun@hotmail.com).
> Maybe it is a good idea to use IRC, I just finished all my finals so I 
> have some time to figure this out. :-)
> 
> Yeah, you are right. After I logged on to the remote host, I will set 
> the DISPLAY variable to be 127.0.0.1:0.0, it worked on some Linux 
> machines, but not all. So I think this maybe a problem with the Linux sshd
configuration.

You are not supposed to do that.  ssh works by redirecting your X apps to
point to a local screen that sshd is listening on.  If the DISPLAY variable
is unset when you login to the remote machine, then it means that the remote
machine is not properly configured for ssh X tunnelling. 
  If it is set, then leave it alone and try running an app... it should work
fine.  That is what I meant when I said to follow the instructions on the
web page; I didn't leave out any steps, which means that I don't want you to
add any steps that I didn't mention.  Please try that and report your
results to the list.

> BTW, what IRC program do you recommend?

I use Mozilla's IRC program called Chatzilla.

Harold

Re: Remote open X application

[Harold L Hunt II]

Welson,

Welson Sun wrote:

> Here is the result:
> 1. Start Cygwin/X
> DISPLAY = 127.0.0.1:0.0
> 
> 2. ssh -X Remote Host
> DISPLAY = My router's external address

So, how do you launch apps from the remote host then?  Are you setting 
the DISPLAY variable on the remote host to point back to the Windows host?

By the way, do you do IRC?  I am in irc.freenode.net/#cygwinx.  It would 
be easier to help you there.

Harold

Re: Remote open X application

[Harold L Hunt II]

Welson,

Welson Sun wrote:

> Thanks Harold.
> 
> At first, I just followed the link you provided, but got the error as stated
> in my previous email. Then I add the "xhost + ... " command before doing
> ssh, and it worked for my Linux machines.
> 
> So, I think it might be that other Linux machines are not correctly set up,
> especially for X tunnelling. I am not expert on this, I need to talk with my
> system administrator. 

Run the following when you login to one of your remote machines and tell 
me if the value of DISPLAY is equal to your Window machine's address or 
your Linux machine's address:

set | grep DISPLAY

Harold

RE: Remote open X application

[Welson Sun]

Here is the result:
1. Start Cygwin/X
DISPLAY = 127.0.0.1:0.0

2. ssh -X Remote Host
DISPLAY = My router's external address


-----Original Message-----
From: cygwin-xfree-owner@cygwin.com [mailto:cygwin-xfree-owner@cygwin.com]
On Behalf Of Harold L Hunt II
Sent: Wednesday, December 17, 2003 8:31 PM
To: cygwin-xfree@cygwin.com
Subject: Re: Remote open X application

Welson,

Welson Sun wrote:

> Thanks Harold.
> 
> At first, I just followed the link you provided, but got the error as 
> stated in my previous email. Then I add the "xhost + ... " command 
> before doing ssh, and it worked for my Linux machines.
> 
> So, I think it might be that other Linux machines are not correctly 
> set up, especially for X tunnelling. I am not expert on this, I need 
> to talk with my system administrator.

Run the following when you login to one of your remote machines and tell me
if the value of DISPLAY is equal to your Window machine's address or your
Linux machine's address:

set | grep DISPLAY

Harold

RE: Remote open X application

[Welson Sun]

OK, I know what's wrong now. The step should be:
1. Start Cygwin X
2. xhost + Remote Server
3. ssh -X Remote Server

This works for me now. At least the "refused by server" is resolved.

But not all Linux machines................

I can start X applications on some Linux machine in this way, but on some
others, it still complains about:
Error: Cann't open display: localhost:0.0

I have no idea, now the problem looks like is relating with the Linux
machine setup. Anybody can help me? Thanks!
 

-----Original Message-----
From: cygwin-xfree-owner@cygwin.com [mailto:cygwin-xfree-owner@cygwin.com]
On Behalf Of Welson Sun
Sent: Wednesday, December 17, 2003 6:18 PM
To: cygwin-xfree@cygwin.com
Subject: Remote open X application

 
Hi all, I have just installed Cygwin-XFree86, it works fine for local X
applications, but when I tried to open remote X application, it fails. The
log is:
 
Xlib: connection to "localhost:0.0" refused by server
Xlib: No protocol specified
 
Error: Cann't open display: localhost:0.0
 
I searched the maillist, looks like a lot of people have been caught by this
problem, but there is no satisfying answer yet.
 
I have set the DISPLAY environment to be 127.0.0.1:0.0, but no help.
I have disabled the NAV, but no help.
 
Looks like it is the problem with my windows X server setting, somehow, it
is not accepting the incoming request.
 
Any idea guys?



Best Regards,

Welson Sun

-------------------------------------
Electrical and Computer Engineering
Brigham Young Unversity
461 CB, Provo, Utah 84602

Office: (801) 422-7206
Email:  welson@et.byu.edu
------------------------------------- 

Remote open X application

[Welson Sun]

 
Hi all, I have just installed Cygwin-XFree86, it works fine for local X
applications, but when I tried to open remote X application, it fails. The
log is:
 
Xlib: connection to "localhost:0.0" refused by server
Xlib: No protocol specified
 
Error: Cann't open display: localhost:0.0
 
I searched the maillist, looks like a lot of people have been caught by this
problem, but there is no satisfying answer yet.
 
I have set the DISPLAY environment to be 127.0.0.1:0.0, but no help.
I have disabled the NAV, but no help.
 
Looks like it is the problem with my windows X server setting, somehow, it
is not accepting the incoming request.
 
Any idea guys?



Best Regards,

Welson Sun

-------------------------------------
Electrical and Computer Engineering
Brigham Young Unversity
461 CB, Provo, Utah 84602

Office: (801) 422-7206
Email:  welson@et.byu.edu
-------------------------------------