Linux Debian support - Remote Desktop Login

Author

Remote Desktop Login

Adrian Hoe

2007-05-13, 1:13 pm

Hi,

I have stopped using Debian Sarge for quite some time. Reason: The
Desktop IU did not look good. Windows and text look very rough at
1024x768.

Recently, I am testing out some distro, OpenSUSE, FC6 and of course
Debian Etch. To my surprise, the UI has improved a lot. I can even get
1280x1024 on my hardware. If I am not mistaken, my graphics card can
only support 1024x768 max. That's miracle. Could anyone explain this
phenomenon? Great job!

Although I have a few Linux boxes and Solaris (SPARC) running, my
major platform is Mac OS X which I use everyday. I setup everything so
that I can do Remote Desktop Login and/or tunnel X over SSH.
Everything is fine.

But I am not able to perform Remote Desktop Login on Debian Etch. The
window shows up with X cursor but no login manager. I am using KDM (I
think, I dpkg-reconfigure gdm and/or dpkg-reconfigure kdm and select
kdm; I have install kdm and kde). I have follow all the setup steps as
in:

http://adrianhoe.com/adrianhoe/2006...login-from-mac/

What have I missed here? Please help. I wish to restart using Debian
for the nice UI and the phenomenon 1280x1024 screen resolution.

Alexander Schestag

2007-05-13, 1:13 pm

Hi,

Adrian Hoe wrote:

> But I am not able to perform Remote Desktop Login on Debian Etch. The
> window shows up with X cursor but no login manager.

I don't have a solution for this, but have you ever tried NX
(http://www.nomachine.org)? It is a small and *very* fast X Server that
can be accessed by an NX client via SSH. You do not need a login screen
anymore, because you login on the client that establishes the connection
via a secure ssh connection. You can also use it with auth login. You
can configure the client start any window manager on the remote machine.
I use NX with fluxbox. And there is one big advantage of NX: speed.
Normal X forwarding is very slow. With NX, you won't see any difference
in speed between your local desktop and the remote desktop.

Caution: There is a package for the NX server in the Debian Etch
sources. *Don't* use this package for it is too old to work with the
newest client. Install *both* the server *and* the client from the
newest sources on http://www.nomachine.org.

Give it a try, I am sure you will love it.

Alex

Adrian Hoe

2007-05-13, 1:13 pm

On May 13, 9:33 pm, Alexander Schestag <a...@schestag.info> wrote:
> Hi,
>
> Adrian Hoe wrote:
>
> I don't have a solution for this, but have you ever tried NX
> (http://www.nomachine.org)?It is a small and *very* fast X Server that
> can be accessed by an NX client via SSH. You do not need a login screen
> anymore, because you login on the client that establishes the connection
> via a secure ssh connection. You can also use it with auth login. You
> can configure the client start any window manager on the remote machine.
> I use NX with fluxbox. And there is one big advantage of NX: speed.
> Normal X forwarding is very slow. With NX, you won't see any difference
> in speed between your local desktop and the remote desktop.
>
> Caution: There is a package for the NX server in the Debian Etch
> sources. *Don't* use this package for it is too old to work with the
> newest client. Install *both* the server *and* the client from the
> newest sources onhttp://www.nomachine.org.
>
> Give it a try, I am sure you will love it.
>
> Alex

But I want to do Remote Login from Mac OS X to Debian Etch on a local
network. Speed is not a problem. Furthermore, according to
Nomachine.com download page, NX Server is available for Debian Woody
and Sarge. Etch is not mentioned.

Mumia W.

2007-05-13, 1:13 pm

On 05/13/2007 08:00 AM, Adrian Hoe wrote:
> [...]
> But I am not able to perform Remote Desktop Login on Debian Etch. The
> window shows up with X cursor but no login manager. I am using KDM (I
> think, I dpkg-reconfigure gdm and/or dpkg-reconfigure kdm and select
> kdm; I have install kdm and kde). I have follow all the setup steps as
> in:
>
> http://adrianhoe.com/adrianhoe/2006...login-from-mac/
>
> What have I missed here? Please help. I wish to restart using Debian
> for the nice UI and the phenomenon 1280x1024 screen resolution.
>

GDM has a gdmsetup command that can enable XDMCP. Perhaps KDM has
something similar.

Alexander Schestag

2007-05-13, 1:13 pm

Adrian Hoe wrote:
> On May 13, 9:33 pm, Alexander Schestag <a...@schestag.info> wrote:
>
>

> But I want to do Remote Login from Mac OS X to Debian Etch on a local
> network.

There is a Mac OS X client.

> Speed is not a problem. Furthermore, according to
> Nomachine.com download page, NX Server is available for Debian Woody
> and Sarge. Etch is not mentioned.

I have it running on Etch. It works great.

This was just a suggestion. You don't have to follow it. :-)

Alex

Adrian Hoe

2007-05-13, 7:13 pm

On May 14, 12:00 am, "Mumia W." <paduille.4061.mumia.w
+nos...@earthlink.net> wrote:
> On 05/13/2007 08:00 AM, Adrian Hoe wrote:
>
>
>
>
> GDM has a gdmsetup command that can enable XDMCP. Perhaps KDM has
> something similar.

I selected "KDM" when I did "dpkg-reconfigure gdm". The login does not
look like K but more like Gnome. But I have both gdm and kdm started
according to the boot log. Is this a problem?

Yes, I have enabled remote login in gdm setup. XDMCP is on.

The window with X cursor appeared on my Mac OS X but no login screen.
--
Adrian Hoe
http://adrianhoe.net

Mumia W.

2007-05-14, 1:13 am

On 05/13/2007 05:52 PM, Adrian Hoe wrote:
> On May 14, 12:00 am, "Mumia W." <paduille.4061.mumia.w
> +nos...@earthlink.net> wrote:
>
> I selected "KDM" when I did "dpkg-reconfigure gdm". The login does not
> look like K but more like Gnome. But I have both gdm and kdm started
> according to the boot log. Is this a problem?
>

You only want one display manager running. Two would probably conflict.

> Yes, I have enabled remote login in gdm setup. XDMCP is on.
>
> The window with X cursor appeared on my Mac OS X but no login screen.

Take a look at the Xorg log on the Debian machine. It should be in
/var/log/Xorg.0.log (or any of /var/log/Xorg.*.log).

Adrian Hoe

2007-05-14, 1:14 pm

On May 14, 1:30 pm, "Mumia W." <paduille.4061.mumia.w
+nos...@earthlink.net> wrote:
>
> Take a look at the Xorg log on the Debian machine. It should be in
> /var/log/Xorg.0.log (or any of /var/log/Xorg.*.log).

Is there any particular stuff I should look at?

--
Adrian Hoe
http://adrianhoe.net

Adrian Hoe

2007-05-14, 1:14 pm

On May 14, 12:58 am, Alexander Schestag <a...@schestag.info> wrote:
> Adrian Hoe wrote:
>
>
>
>
>
>
> There is a Mac OS X client.
>
>
> I have it running on Etch. It works great.
>
> This was just a suggestion. You don't have to follow it. :-)
>
> Alex

Yeah I know. Thanks for the info. I did not know such thing like NX
exists. I like to try out NX but it will be some hassle to install NX
to every boxes. After all, I have no problem with Solaris and other
linux boxes. I would rather have all my boxes to be the same way.
--
Adrian Hoe
http://adrianhoe.net

AJackson

2007-05-14, 7:13 pm

On May 14, 4:44 pm, Adrian Hoe <aby...@gmail.com> wrote:
> On May 14, 1:30 pm, "Mumia W." <paduille.4061.mumia.w
>
> +nos...@earthlink.net> wrote:
>
>
> Is there any particular stuff I should look at?

You should look into /var/log/messages about kdm and gdm.
One will tell you that it starts, the other that it isn't started
becouse there is another X display manager started/selected.

IF you run kdm, it doesn't matter if you change any settings for gdm
(and vice vesa).
You could also try this command:
ps -A | grep '.dm'
There you should have one of kdm or gdm (one or more lines).

If you want to see of you will be abel to log in on X remote, you
could try:
nmap localhost
You should also try with your IP number or hostname to get what others
see on your machine.
This will tell if there is any X11 XDMCP running on your host.

Good luck

Adrian Hoe

2007-05-16, 1:14 am

On May 15, 6:24 am, AJackson <anders.jack...@gmail.com> wrote:
>
> You should look into /var/log/messages about kdm and gdm.
> One will tell you that it starts, the other that it isn't started
> becouse there is another X display manager started/selected.
>
> IF you run kdm, it doesn't matter if you change any settings for gdm
> (and vice vesa).
> You could also try this command:
> ps -A | grep '.dm'
> There you should have one of kdm or gdm (one or more lines).
>
> If you want to see of you will be abel to log in on X remote, you
> could try:
> nmap localhost
> You should also try with your IP number or hostname to get what others
> see on your machine.
> This will tell if there is any X11 XDMCP running on your host.
>
> Good luck

This is my nmap result:

Starting Nmap 4.11 ( http://www.insecure.org/nmap/ ) at 2007-05-16
09:16 MYT
Interesting ports on localhost (127.0.0.1):
Not shown: 1674 closed ports
PORT STATE SERVICE
22/tcp open ssh
25/tcp open smtp
111/tcp open rpcbind
113/tcp open auth
631/tcp open ipp
31416/tcp open boinc-client

Nmap finished: 1 IP address (1 host up) scanned in 0.286 seconds

I checked and the kdm is running but the login manager looks like gdm
with different menu set.

I think the XDMCP is running because I am able to get a blank screen
and X cursor on my Mac when I run Xnest. I am able to move the X
cursor with the mouse connected to my Mac Mini. I believe I have been
connected to my Debian box, the login manager just won't come up.

Should I look into something where I could have missed something else?

Thanks.
--
Adrian Hoe
http://adrianhoe.net

Mumia W.

2007-05-16, 1:14 am

On 05/15/2007 08:19 PM, Adrian Hoe wrote:
>
>
> This is my nmap result:
>
> Starting Nmap 4.11 ( http://www.insecure.org/nmap/ ) at 2007-05-16
> 09:16 MYT
> Interesting ports on localhost (127.0.0.1):
> Not shown: 1674 closed ports
> PORT STATE SERVICE
> 22/tcp open ssh
> 25/tcp open smtp
> 111/tcp open rpcbind
> 113/tcp open auth
> 631/tcp open ipp
> 31416/tcp open boinc-client
>
> Nmap finished: 1 IP address (1 host up) scanned in 0.286 seconds
>
>

That only lists open TCP ports. Use "netstat -ptul" to list both TCP and
UDP listening ports. XDMCP should be on UDP port 177.

If you are root, it will show which program is listening on the XDMCP
port: either gdm or kdm; I advise disabling the display manager that
isn't being used; hint: disable kdm.

> I checked and the kdm is running but the login manager looks like gdm
> with different menu set.
> [...]

Adrian Hoe

2007-05-16, 7:13 am

On May 16, 2:08 pm, "Mumia W." <paduille.4061.mumia.w
+nos...@earthlink.net> wrote:[vbcol=seagreen]
>
> That only lists open TCP ports. Use "netstat -ptul" to list both TCP and
> UDP listening ports. XDMCP should be on UDP port 177.
>
> If you are root, it will show which program is listening on the XDMCP
> port: either gdm or kdm; I advise disabling the display manager that
> isn't being used; hint: disable kdm.
>

Here's the netstat. There seems no port 177:

udp 0 0 *:1025
*:* 2571/avahi-daemon:
udp 0 0 *:770
*:* 2714/rpc.statd
udp 0 0 *:1028
*:* 2714/rpc.statd
udp 0 0 *:mdns
*:* 2571/avahi-daemon:
udp 0 0 *:sunrpc
*:* 2069/portmap
udp 0 0 *:ipp
*:* 2496/cupsd

I checked the gdm, XDMCP is on. Is there any package that I need to
install?
--
Adrian Hoe
http://adrianhoe.net

Mumia W.

2007-05-16, 1:14 pm

On 05/16/2007 06:16 AM, Adrian Hoe wrote:
> On May 16, 2:08 pm, "Mumia W." <paduille.4061.mumia.w
> +nos...@earthlink.net> wrote:
>
>
> Here's the netstat. There seems no port 177:
>
> udp 0 0 *:1025
> *:* 2571/avahi-daemon:
> udp 0 0 *:770
> *:* 2714/rpc.statd
> udp 0 0 *:1028
> *:* 2714/rpc.statd
> udp 0 0 *:mdns
> *:* 2571/avahi-daemon:
> udp 0 0 *:sunrpc
> *:* 2069/portmap
> udp 0 0 *:ipp
> *:* 2496/cupsd
>
> I checked the gdm, XDMCP is on. Is there any package that I need to
> install?

I don't think so. I have no idea what's blocking your gdm's XDMCP. It
works here (Debian Sarge, i386). I could imagine that kdm is conflicting
with gdm, but that's probably not the problem either.

Under the section titled grasping at straws to troubleshoot a problem, I
have this item: On the Debian machine, first disable kdm, then start a
"script" session and run "netstat -cult"; in another X terminal, su to
root and run gdmsetup; disable XDMCP and close gdmsetup; then relaunch
gdmsetup and re-enable XDMCP; while you're still in gdmsetup, go into
the security tab and enable TCP connections (but this should not be needed).

If XDMCP is still not there, I'm completely out of ideas.

You can stop netstat by hitting Control-C; the output will be recorded
by script, so you can peruse it to see if XDMCP showed up at any time
during the session.

Good luck.
-------------------
Oh wait, I seem to have this filed under "Grasping at ½ straws": See if
you can do XDMCP from your Etch machine to itself:

From a virtual console, try this:
xinit -- :1 -query localhost -once

There's no point in doing this until some software on your computer
starts trying to listen on the XDMCP protocol port 177.

AJackson

2007-05-17, 1:14 am

On May 16, 5:20 pm, "Mumia W." <paduille.4061.mumia.w
+nos...@earthlink.net> wrote:
> On 05/16/2007 06:16 AM, Adrian Hoe wrote:
>
>
>
nd[vbcol=seagreen]
>
>
>

Then you don't have any *dm mannager running and listening on X login
attemts from other X-servers.
[vbcol=seagreen]
>

Look at your logs! It's there for you to use when you have problems.
Just becouse you have the package install, doesn't mean that it's
servers
is running.
[vbcol=seagreen]
> I don't think so. I have no idea what's blocking your gdm's XDMCP. It
> works here (Debian Sarge, i386). I could imagine that kdm is conflicting
> with gdm, but that's probably not the problem either.

No problem have them both installed. They check which one to use
(selected when you install the package). If you want to change, or
check,
try this in a terminal on the server.

sudo dpkg-reconfigur -plow gdm

Then you can change which X display manager you want to have.

> Under the section titled grasping at straws to troubleshoot a problem, I
> have this item: On the Debian machine, first disable kdm, then start a
> "script" session and run "netstat -cult"; in another X terminal, su to
> root and run gdmsetup; disable XDMCP and close gdmsetup; then relaunch
> gdmsetup and re-enable XDMCP; while you're still in gdmsetup, go into
> the security tab and enable TCP connections (but this should not be neede=
d).

> If XDMCP is still not there, I'm completely out of ideas.

> You can stop netstat by hitting Control-C; the output will be recorded
> by script, so you can peruse it to see if XDMCP showed up at any time
> during the session.
>
> Good luck.
> -------------------
> Oh wait, I seem to have this filed under "Grasping at =BD straws": See if
> you can do XDMCP from your Etch machine to itself:
>
> From a virtual console, try this:
> xinit -- :1 -query localhost -once
>
> There's no point in doing this until some software on your computer
> starts trying to listen on the XDMCP protocol port 177.

You could also try to run Xnest to query, if you are logged into the
server.

Xnest :1 -query localhost

Just another way of doing same thing

Good luck

Adrian Hoe

2007-05-17, 7:13 am

On May 16, 11:20 pm, "Mumia W." <paduille.4061.mumia.w
+nos...@earthlink.net> wrote:

> "script" session and run "netstat -cult"; in another X terminal, su to
> root and run gdmsetup; disable XDMCP and close gdmsetup; then

When I run "netstat -cult", it shows:

....
udp6 0 0 *:xdmcp
*:*

Does this mean xdmcp is already running? I am running kdm and I have
already checked /etc/kde3/kdm/kdmrc. Everything looks fine in kdmrc.
--
Adrian Hoe
http://adrianhoe.net

Adrian Hoe

2007-05-17, 7:13 am

On May 16, 11:20 pm, "Mumia W." <paduille.4061.mumia.w
+nos...@earthlink.net> wrote:
> Oh wait, I seem to have this filed under "Grasping at =BD straws": See if

Please pardon my ignorance. What do you mean? Google returned nothing
about "Grasping at =BD straws" related to Debian/Linux except this
thread.
--
Adrian Hoe
http://adrianhoe.net

Mumia W.

2007-05-18, 1:14 am

On 05/17/2007 02:22 AM, Adrian Hoe wrote:
> On May 16, 11:20 pm, "Mumia W." <paduille.4061.mumia.w
> +nos...@earthlink.net> wrote:
>
> Please pardon my ignorance. What do you mean? Google returned nothing
> about "Grasping at ½ straws" related to Debian/Linux except this
> thread.

Ignore it; it's just a joke about "grasping at straws." If you don't
know the idiom just google it.

Mumia W.

2007-05-18, 1:14 am

On 05/17/2007 02:18 AM, Adrian Hoe wrote:
> On May 16, 11:20 pm, "Mumia W." <paduille.4061.mumia.w
> +nos...@earthlink.net> wrote:
>
>
>
> When I run "netstat -cult", it shows:
>
> ....
> udp6 0 0 *:xdmcp
> *:*
>
> Does this mean xdmcp is already running? I am running kdm and I have
> already checked /etc/kde3/kdm/kdmrc. Everything looks fine in kdmrc.
> --
> Adrian Hoe
> http://adrianhoe.net
>
>

XDMCP is active on your computer; use this command to see what program
is listening on the XDMCP port:

netstat -pul

For me, it's gdm. And don't forget to test if your Debian computer can
do XDMCP from itself to itself:

xinit -- :1 -query localhost -once

If that works (it allows you to log in), then the next step is to find
out what part of the network is blocking XDMCP/X11 communications.

Adrian Hoe

2007-05-22, 7:14 pm

On May 18, 11:21 am, "Mumia W." <paduille.4061.mumia.w
+nos...@earthlink.net> wrote:
> On 05/17/2007 02:18 AM, Adrian Hoe wrote:
>
>
>
>
>
>
>
>
> XDMCP is active on your computer; use this command to see what program
> is listening on the XDMCP port:
>
> netstat -pul
>
> For me, it's gdm. And don't forget to test if your Debian computer can
> do XDMCP from itself to itself:
>
> xinit -- :1 -query localhost -once
>
> If that works (it allows you to log in), then the next step is to find
> out what part of the network is blocking XDMCP/X11 communications.

When I logged in as user and run xinit, an error occured:

X: user not authorized to run the X server. Aborting.

I have to logged in as root and I am able to log in at another
session. I am able to toggle between 1st and 2nd session using CTRL-
ALT-F7 and -F8.
--
Adrian Hoe
http://adrianhoe.net

Mumia W.

2007-05-23, 1:14 am

On 05/22/2007 01:13 PM, Adrian Hoe wrote:
> On May 18, 11:21 am, "Mumia W." <paduille.4061.mumia.w
> +nos...@earthlink.net> wrote:
[vbcol=seagreen]
>
>
> When I logged in as user and run xinit, an error occured:
>
> X: user not authorized to run the X server. Aborting.
>
> I have to logged in as root and I am able to log in at another
> session. I am able to toggle between 1st and 2nd session using CTRL-
> ALT-F7 and -F8.

XDMCP is running on your Debian system, but some part of the
authorization system may be blocking logins.

You should be able to do an XDMCP login as a regular user. I'm out of
ideas. My advice is this:

* Disable kdm and concentrate your efforts on getting gdm configured.
* Follow the other advice given previously in the thread, e.g. enable
TCP connections in gdm and investigate if the network is blocking some
parts of X11 or XDMCP communications.
* Run "nmap" (the network mapper) from the Mac; both X11 and XDMCP ports
should be open on the Debian machine.

Good luck.