Hi,

don't know, if that helps but perhaps there is a local installation of
firebird/interbase _server_ on that clients?

A few days ago we had some trouble with the following: Server: Firebird
V1.5, Clients: Clientinstallation of V1.5. Then another application was
installed on one of the clients. Including a complete installation of
Firebird Superserver 1.5 and changed port (3051) in the "firebird.conf" (the
server was installed on the client!). After that the client could'nt reach
the (my) Server-DB anymore.

With regards
Thomas