David,

t> They are running NT4 Server sp6 with Win98 clients. After asking on
t> the IBObjects forum someone suggested a firewall as a possible
t> cause. They do run a firewall on their router, but I wouldn't have
t> expected that to block local traffic, nonetheless I need to
t> investigate it.

many corporate firewalls selectively block local traffic.

t> What ports/protocol do the events use?

taken from your firebird.conf file:

#
# The TCP Port Number to be used for server Event Notification
# messages. The value of 0 (Zero) means that the server will choose
# a port number randomly.
#
# Type: integer
#
#RemoteAuxPort = 0

So you can choose the port at will. If you don't set it (default), the server
will choose one, which isn't a good solution if one has a firewall to
configure. So choose a port number and tell the firewall what it is.
It should work then.

Ciao
--
Nando mailto:nandod@...