1. Norwalk LUG May Meeting
FreeNX
Presentation for the
Norwalk LUG May Meeting
May 7, 2014
by Chris Habasinski

2. FreeNx – What is it?
A remote display technology which provides near local speed application responsiveness over high latency, low bandwidth links
Requires a server and client component
Use it when you need to run GUI Linux apps over a remote connection – including a full remote desktop
Also works on the LAN
Resources:

3. FreeNX – Who is it? The core libraries are GPL'ed by NoMachine
FreeNX is the GPL implementation of the NX Server and Client
NoMachine provides a free 2 client NX Server
FreeNX has no usage limitations
OpenNX is the client implementation – compatible with the NoMachine client

4. FreeNX – Key Features Fast Secure – uses ssh Session resilience
Supports remote audio and printing
Clients for Linux, Windows, MacOS and Unix
(NoMachine, OpenNX, plugins (Remmina)

5. FreeNX - Alternatives VNC RDP Remote X11 Exceed on Demand
Xephyr (Mac OSX)

6. FreeNX – How it Works
NX Compression: NoMachine have developed their own compression algorithm for X traffic. This is about 10 times more efficient than generic ZLIB compression, while using only one tenth of ZLIB's CPU cycles. This is the first secret for NoMachine's NX speedup.
NX Caching: NoMachine have also developed a very intelligent caching mechanism for X11 traffic. It produces a quite big "hit rate", sparing the transfer of the same data repeatedly, and restricting the transfer of similar data to a "differential transfer" only. This is the second secret for NoMachine's NX speedup.
NX Roundtrip Suppression: Before NX there was no known method to suppress X11 roundtrips over remote links reliably and in a robust way. NX can do that by translating X11 traffic at the remote end (occuring from application to nxagent) into NX protocol traffic. This is the third secret for NoMachine's NX speedup.
Overall efficiency: All 3 methods combined are able to achieve a 70-fold efficiency of working with a remote X11 GUI using the highest level of compression over low bandwidth/high latency links. (Note: the "Modem" compression type [as shown in the NoMachine NX Client GUI] is the best compression, "LAN" setting does no compression at all. You can use "modem" compression in LANs for better efficiency.)

7. FreeNX – Installation & Configuration
Ubuntu
Add repo
Install
Download separate setup utility
Configure – authentication, session options
CentOS
Install (in the default repos)
Soalris requires 3 packages to be installed. In order:
nxclient
nxnode
nxserver

8. FreeNX - Tips Configure to use key authentication
Do not use the default keys
Add '-norender' option to AGENT_EXTRA_OPTIONS_X
OpenNX client and NoMachine client package files overwrite each other – use one of the other
XQuartz (v 2.7.5) bug in MacOS 10.9 prevents Xephyr from starting up a nested X session – use OpenNX

9. FreeNX – Administration
nxserver command – run as administrator
start | stop | status | restart
list
listuser, adduser, password, deluser
terminate, force-terminate
suspend
cleanup