I have an Delphi 7 application that runs fine on the LAN and over a
VPN at a number of sites. However, at one site the application runs
fine over the LAN, but a PC that connects to it over the VPN is
causing me problems. The application connects OK, which involves some
data being read from and written to a database, but when the user
attempts to read further data to one of the forms in the application,
I get the 'connection forcibly closed by remote host' error message.
If I look in the FB log file there are no entries relating to errors.
The customer shut down his server over christmas and the only entry in
the log file since then is the one relating to restarting FB. There
are also no error messages in the event log on the server.

My question is, is the 'host' referred to Firebird or the server on
which it is running? Excuse my ignorance, but I need to clear this up.
Reading the posts here and on other sites relating to this error I
gather this is a rather intractable problem. This VPN connection has
always been a bit dodgy, due we think to a combination of a poor ADSL
connection and a router not really suited to use with a VPN but in the
past has worked, albeit slowly. The problem started when the routers
at either end of the VPN was changed for better quality equipment.

Using FB 1.53 on Windows 2000 server.