I've discovered a Firebird's major problem, and i don't know how to solve it.
I have two apps updating the same record using transactions. If one app has a connection failure and didn't get the chance to commit, the other app hangs, waiting for the other app to commit, but that will never gonna happen, until you do a restart of the firebird server.
If anybody knows a method on how to solve this problem, without the "dummy packet" option because that is not a safe one, i appreciate.
Thanks.

ever heard of transaction timeouts? You likely have those set to unlimited, set it to something decent and the transaction from the crashing application should time out causing a rollback.

Where can i set the transaction timeout in Firebirs 1.5.3?

I found where i can set the transaction timeout, but this doesn't solve my problem, because the server still block other clients which tries to access those records. In this case the server should be able to recognize transactions that had been disconnected and to kill them. Do you know how can i solve this problem?

I'm new to Firebird, but according to manual Firebird doesn't auto commit/rollback transaction manualy.
You must (handle) commit/rollback it manualy if exception happen.