[FreeNX-kNX] FreeNX+QGIS: reproducible connection shut downs

[Maciej Sieczka]

Dear All

I've been having a very strange problem with FreeNX. Most of the time 
connection is all OK.

However, when I display more complex vector data in QGIS (a FOSS GIS 
software) on the server via NX, which take some time to render, the 
connection is shut down after about 1 second the rendering starts. The 
client yields an error "The connection with the remote server was shut 
down. Please check the state of your network connection."

When I try to login back right after that I get to the point when 
desktop is getting redrawn, until it's the QGIS window part - then 
connection is shut down again. If I wait half a minute before loging 
back, I get to the remote desktop OK, with the contents of QGIS window 
rendered already. Once I refresh/resize it however, the connection gets 
shut down again instantly.

Now the funniest part - this all happens only when I set up connection 
as MODEM/ISDN/ADSL/WAN. It never happens when the connection is set to 
LAN. It doesn't depend whether I really connect to the server from the 
local network or from home via adsl connection - "LAN" never 
disconnects, other always do when displaying more vectors in QGIS. Using 
same version of QGIS locally on same machines with same data works just 
OK, but it breaks remote NX sessions as described.

The problem is not dependent on client hardware either. Different 
clients (Ubuntu Dapper i386, Ubuntu Gutsy i386/amd64, Debian testing 
i386, Windows XP, 2000) and one server - same pattern. The server is 
running amd64 Gutsy, freenx 0.7.1.

Now using !M NX clients 3.1.06. The pattern was reproducible with 2.0 
clients too. Disabling/enabling any options in the client does not 
change anything.

Any ideas what could be the culprit? It's driving me nuts. Please help. 
Searching the ML archive and googling around didn't.

If anybody is willing to try to reproduce the error, QGIS is really easy 
to install for most platform, as described on [1]. The sample data to 
reproduce the crash are at [2]. Just install QGIS, start it, "add 
layer", point at the CROPA.shp from sample data - it should kaboom.

[1]http://download.qgis.org/downloads.rhtml
[2]http://www.biol.uni.wroc.pl/sieczka/udostepnione/vmap0.tar.bz2

If I can give more info by providing some logs please let me know.

Cheers
Maciek