Xdmcp broadcast broken

[uli42]

With a properly configured xdm in the network

Xnest :22 -broadcast

works (shows a display manager login window), while

nxagent :22 -broadcast

does not. It starts an ordinary desktop nxagent session.

However, nxagent :22 -query <xdmcpserver> and nxagent :22 -indirect <xdmcpserver> work!

Watching the xdm log on the server side shows that no broadcast msg is reaching the server while with Xnest it does.