Ive started to get errors when attempting to connect to headless linux systems. The errors reported by vairious clients are

dmcp: received an ACCEPT message
Xdmcp: sent a MANAGE message.
Xdmcp: Timed out, state 8. Retransmissions: 0
Xdmcp: sent a MANAGE message.
Xdmcp: Timed out, state 8. Retransmissions: 1

and variations of the above. It is affecting all linux boxes on the network. Only changes recently have been dhcp servers. and all the linux systems use fixed ip addresses outside of the dhcp allocation pool.

I can
ping each host from a client
ping the client from each post (locally)
recieve system mail from the hosts
access samba shares on the hosts

but i cant
xdmcp or ssh into the host computers.

the firewall on the network only affects traffic leaving the network not lan traffic.

Has anybody got any ideas on how to solve this or a possible cause.

All the systems are running debian etch
clients ive tried: xmanager under windows, xdmcp chooser under debian, xming under windows.

XDMCP requires being able to look up the name of a computer

so therfore the dns server on the network must have entries for the hosts involved.
If clients are not on the dhcp server the dns will need there entries manually.

And remember the xdmcp chooser in gdm is buggy and slightly unstable.