[K12OSN] remote login

Petre Scheie petre at maltzen.net
Wed Sep 22 16:16:26 UTC 2004

I'm sure your k12box already has a static IP address, but the public 
address that Adelphia assigns to the first box past the cable modem--in 
your case, that would be the IPCop box, and that is likely a dynamic 
address. If it were a static address, that would be easier, but they 
cost more than dynamic addresses.  But there are ways around that, too:

Check out www.dyndns.org.  With them you can get up to five subdomains 
for free, and they have a bunch of domains to choose from.  So, for 
example, my home webserver's DNS name is petre.homedns.org.  Dyndns owns 
the homedns.org domain, and I signed up for the petre part of that 
domain.  Then, you download onto the ipcop box a dynamic agent that 
periodically looks at the address that your ISP has assigned to you and 
then it goes and updates the address in dnydns's DNS servers.  I use 
ddclient which runs as a daemon and checks my address every five 
minutes.  That way, when I want to get to one of my home boxes, I just 
ssh to petre.dyndns.org, and I never have to worry about what the 
address is.  IPCop may even have a built-in client that can update 
dyndns.org.  There are other free DNS services out there; dyndns.org is 
just the one that I'm familiar with.


Will Hatch wrote:

>I don't completely understand your instructions yet, although they seem very good and I think I could figure this out.  But, I'm thinking that I need a static ip address for my k12box, which I do not have.  Adelphia provides internet for free because we are a school within a certain distance from the line.  Do I need a static ip?  Thanks Petre
>>From: Petre Scheie <petre at maltzen.net>
>>Date: 2004/09/22 Wed AM 10:42:40 EDT
>>To: "Support list for opensource software in schools." <k12osn at redhat.com>
>>Subject: Re: [K12OSN] remote login
>>With a few assumptions, 1) that you can ssh into the Ipcop box from 
>>wherever you'll be doing your presentation; 2) that the VNC server is 
>>running on the K12lstp box (which it is by default, but some take it out 
>>if they have no use for it); you'll have a Linux box at the 
>>demonstration site--I don't know if this can be done with a Windows 
>>box.  With those things in place, you can do this:
>> From the remote location (where you'll be standing when doing your 
>>presentation) at a shell prompt, type
>>ssh -C -L 3700:k12lstpbox:5900 ipcopbox
>>where k12ltspbox is the name of the k12ltsp server (and ipcop knows the 
>>address of that box--if not, use the address of the ltsp box), and 
>>ipcopbox is the publicly accessible name or address of your school/ipcop 
>>firewall.  This assumes that the ID you are using on the linux box at 
>>the demo site is valid on the ipcop box; if not, add '-l valid_id' where 
>>valid_id is a legit ID on the ipcop box.  Once that's connected, on the 
>>linux box at the demo site, fire up vncviewer and point it at 
>>localhost:3700, and you should get the LTSP login screen just as if you 
>>were at the school and pointed vncviewer at the server.
>>What the above command does is creates a compressed (-C) tunnel in which 
>>anything directed at port 3700 is sent to the ipcopbox which then 
>>automatically directs the traffic to port 5900 (where vncserver listens) 
>>on the K12ltspbox.
>>I use this regularly to securely connect to remote LTSP servers where I 
>>need to actually see the desktop in action.  It can be a bit slow, 
>>depending on the size of the pipes and the load on the ipcop box and the 
>>ltsp server, but it's certainly usable, especially for a demo.  You 
>>could even take, say, two or three laptops (borrow some and use knoppix 
>>disks to get an instant linux client) to the demo site and have them all 
>>doing this to really show off.  I'd test it beforehand though just to 
>>make sure it doesn't bog down too much.
>>Will Hatch wrote:
>>>Hi all,
>>>I am taking a education class where we have to make a powerpoint presentation on a educational topic.  I want to talk about open source software in schools, and to show what I have done here at this school with recycled computers and the k12 package.  I though it would be cool to be able to remotely login to my server while doing my powerpoint presentation.  Then, I could show how it actually works.  How do I do this and is it too complicated for this rookie?  Also, I have a Ipcop box between my cable modem and my k12 box, as a firewall/router with dansguardian content filtering; in case this complicates things.  Thanks!
>>>K12OSN mailing list
>>>K12OSN at redhat.com
>>>For more info see <http://www.k12os.org>
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>>K12OSN at redhat.com
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