Since the manual of GMS 2.0.3 for Linux is not very helpfull, I would like to share my solution of placing a GMS box behind the firewall.

Like a lot of companies, ours is very small, and for the 3 GMS users we have we have used an old server, installed it with Linux. And since it is not clear in the manual, disabled the linux Apache server.

Our network config is simple, with an wireless router on the internal network.
Our phones can connect to this router, but since the GMS server was also on the internal network, we could not reach it from the inside.

Now you can probably use the GMS gateway, but since there is no manual for that I did the following : I used my Novell 6.5 Apache server as proxy server.

1) Edit your httpd.conf file in sys:\apache2\
2) Remove the # before LoadModule proxy_http_module modules/proxyhtp.nlm
To load your http proxy module in apache upon startup.
3) Now enter the following code :
# Proxy to GMS Server
<IfModule mod_proxy.c>
ProxyRequests Off
ProxyPass /mobile/ http://<ipadress GMS server>/
ProxyPassReverse /mobile/ http://<ipadress GMS server>/
4) restart your Apache server on netware
5) Done !

This is ( I think ) a beautifull way for the GMS to work
Now you can just type :
http://<Public DNS name of your Netware server>/mobile/
and you have reached your GMS server !
Also put this as the server adress in your phones and in the setup of your GMS system. (just like the big guys !)