Q: How to "freeze" LTSP sessions - and unfreeze later.

[Ralf Gesel|ensetter <rgx@gmx.de>]

Hi there, 

know that situation? You want to explain something that would last only 
2 minutes - if not you had to detach 25 pupils from "their" computer 
sites?

If one could only halt their sessions - so they won't be distracted for 
the next 2 minutes.

I tried out several things, one worked: Assuming _you_ are on a 
workstation and pupils use thin clients, log in to ltspserver and 
"ifdown" eth0 (presuming eth0 has the 192-net).

At once, all thin clients freeze. Alas, after some time, an ifup of eth0 
doesn't reactivate the sessions - they are timed out and closed (as 
opposed to nx sessions BTW).

Is there any other services that I could use to have the same effect? 
Maybe just start a process with real time priority?

Regards
Ralf