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>	GDM also supports the X Display Manager Protocol (XDMCP) for
	managing remote displays.
      </P
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>	GDM listens to UDP port 177 and will repond to QUERY and
	BROADCAST_QUERY requests by sending a WILLING packet to the
	originator.
      </P
><P
>	GDM can also be configured to honor INDIRECT queries and
	present a host chooser to the remote display. GDM will
	remember the user's choice and forward subsequent requests to
	the chosen manager.
      </P
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>	GDM only supports the MIT-MAGIC-COOKIE-1 authentication
	system.  Little is gained from the other schemes, and no
	effort has been made to implement them so far.
      </P
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>	Since it is fairly easy to do denial of service attacks on the
	XDMCP service, GDM incorporates a few features to guard
	against attacks. Please read the XDMCP reference section below
	for more information.
      </P
><P
>	Even though GDM tries to outsmart potential attackers, it is
	still adviced that you block UDP port 177 on your firewall
	unless you really need it. GDM guards against DoS attacks, but
	the X protocol is still inherently insecure and should only be
	used in controlled environments.
      </P
><P
>	Even though your display is protected by cookies the XEvents
	and thus the keystrokes typed when entering passwords will
	still go over the wire in clear text. It is trivial to capture
	these. You should also be aware that cookies, if placed on an
	NFS mounted directory, are prone to eavesdropping too.
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