Remote login to Linux

[c123]

Just use VNC, using a putty tunnel for security... you don't have to install anything server-side, and the VNC viewer for windows is a very small download (couple of hundred kb).

If you're not sure of how to do any of this, do a quick google of post back here.

[3rd edit / addition]
I'd recommend VNC 'cos it's free, open source, and easy to implement, but you do have two other options as OErjan suggests:

1. cygwin's xfree X Windows server
free, open source, but I'm not sure how easy it is to setup (do you really want to have to setup and configure an X Windows server under MS Windows??).

2. commercial X Windows server
costs money, not open source, however may be easier to setup and performance is likely to be better than with cygwin. one commercial x server I know people use at work is Xceed (see http://fusion.gat.com/docview/x-servers.html which lists and links to this one and others).

HTH

[A. Jorge Garcia]

OK, if I use a WIMPdoze VNC client, I'll have to leave a vnc server running at school, right?

TIA,
AJG

[OErjan]

yes

[c123]

OK, if I use a WIMPdoze VNC client, I'll have to leave a vnc server running at school, right?

TIA,
AJG

Not necessarily, you could start the VNC server only when you need a desktop, from the command line that you get in Putty. It's best to use VNC via an SSH tunnel for the following reasons:

1. security
VNC by itself is not secure, and although I've never heard of anyone sniffing a password or other info from a VNC session, why take the chance? Espceially if you're going to open a putty session for a command line anyway.

2. firewalls
just one port to open (for SSH), and that can be anyone you like (even 80 or 443 etc)

3. resources
you just start a VNC session when you need one ("vncserver 1", in putty you'd connect to "localhost:5901")

HTH

p.s. by default VNC loads a lightweight window manager (like twm), but you can use KDE or anyother if you want.

[A. Jorge Garcia]

OK, c123, let me see if I understand you. Do you mean for me to open a ssh via putty on my wife's WIMxP box, start a vncserver thru ssh once logged-in and also run the vncviewer localhost:1 thru ssh?

How can this work. Don't I need to run the vncviewer on the XP box to be able to get graphics on there. You must be thinking that I'll be logging-in from a Linux box too. Well, then there's no problem. I can already do this without vnc and get KDE apps to run.

What I'd like to do is get KDE apps to run thru ssh (putty) on the XP box with vnc. Now, I tried this. I used putty to log-in to my ssh server at school. I can do any console app I please, but no X or KDE. For example, I used joe to write a console app java program and I could use javac to compile the code and java to execute it. All went well with no graphics.

Then, I tried vnc thru the ssh as you suggest and got a "can't open display" error when I ran vncviewer localhost:1. I then went to www. realvnc.com and downloaded the WIMPdoze vnc client and tried to connect to a vncserver I setup at school. When I run vncviewer from the XP box, I get a dialog box asking for the vncserver:display which I provided and then nothing happens.

I don't get this. Can I use vnc or not???

TIA,
AJG

[garyng]

you need to enable the port forwarding in putty. What it does is to forward a local port to the remote host(another port) through ssh. Then on your server, you can start vncserver as usual.

From your xp, you access the local port created by puttyinstead of going to the remote ip) so it would be like 'localhost:1', depending on what local port you tell putty to forward.

edit: forgot to say, it is under the SSH->tunnel section when you start putty

[A. Jorge Garcia]

OK, I tried connecting as you said, c123, to my KNOPPIX server at school from my KNOPPIX server at home and was asked for a passwd. I didn't make a passwd when starting vncserver and none was generated, so what do a I do in this case?

TIA,
AJG

[A. Jorge Garcia]

garyng, lets see if I understand you rightly.

I start putty with X11 forwarding on (from ssh/tunneling). I login to my ssh server at school. I start a vncserver. Then I issue the command line vncviewer localhost where x is the vncserver desktop generated.

Is that all correct? Well, I must be missing something as it won't connect. This is what I get:

apcs@CentauriPrime:~$ vncviewer localhost:1
VNC viewer version 3.3.7 - built Jul 18 2003 16:45:54
Copyright (C) 2002-2003 RealVNC Ltd.
Copyright (C) 1994-2000 AT&T Laboratories Cambridge.
See http://www.realvnc.com for information on VNC.
X connection to localhost:10.0 broken (explicit kill or server shutdown).


What am I doing wrong? Please help, I'd love to get this to work for my students who can't hdinstall KNOPPIX or use a liveCD at home.

TIA,
AJG

[garyng]

Assuming you want to VNC from windows to linux, here is what you need to do :

1. In putty dialog, enable port forwarding(not X11 forwarding), it is the lower dialog. You choose one for local(the window machine) and one for linux(in iport form). So say you choose 5900 for the local(Source Port) and linux.acme.com:5900(Destination).

2. login to linux as usual through putty.

3. start vncserver in the linux prompt(usual parameter), if you use other ports than 5900(if you have local X server), you need to change the Destination in (1)

4. sart vncviewer ON Windows, not on linux and choose local:0(assuming you choose 5900 as the "Source Port" in (1)

Now your vncviewer on XP would go through local port 5900(machine it is running) which is being forwarded by putty(as it is running) to linux port 5900 that you have ssh into. The vncserver on linux is listening to this port and would start a new xsession as usual.

If you also run the putty agent on Windows, you can also use RSA so you don't need to give any username/password(assume the ssh server is setup this way).

As for the password, I believe the vncserver would ask you once when it didn't see any in the home directory. It is a hidden file(.something) and would be used in a future invocation.

[c123]

Hello again,

Admittedly the first time you tunnel a VNC connection it is a bit tricky and can require a small leap of faith (did for me anyway). However garyng has nicely detailed all the steps you need to do from home (i.e. see your nice linux desktop from school on your winxp laptop at home). Just a couple of points though WRT garyng's post:
- destination should be 'localhost' unless you want to see the desktop of a third linux machine (i.e. a machien differnent to the one you are logging into)
- AFAIK you must use 'localhost' (or its IP address 127.0.0.1); 'local' will not work
- using public keys to authenticate is a great idea, but first of all just get password authentication working :)

Sorry, should have posted the following earlier http://www.benjamin.weiss.name/putty-tunnel.html

The page runs you through a real world example - it's like garyng's guide, except you get pictures too :) Note that in the example above, the author is forwarding port 5904 - this corresponds to display :4. [[ the command to start a VNC server on display :4 is 'vncserver :4'; as you see on the page, on the Windows box the user gives 'localhost:4' as the server to connect to]].

AJG, the reason you tell your VNC viewer to connect to display 4 of localhost (= port 5904) is that Putty is forwarding this port, i.e. anything you send to port 5904 on localhost (your winxp laptop) is actually being forwarded to port 5904 on your linux server...

WRT passwords, VNC should ask you to create one when you create a server if one does not already exist. 'vncpasswd' should allow you to create/modify the password (for the current user).