Imported from previous forum
[ original email was from Paolo Aloe - ]
In our implementation, when the process that is serving a FIX session detects that an abnormal condition occurred in the rest of the system which would make it impossible to “safely” continue the session, it sends a Logout message with a brief explanatory text and closes the session. When the abnormal condition has been corrected, the process detects it and either starts listening again for incoming connections if it’s on the server side or tries to reconnect if it’s on the client side. In either case sequence numbers definitely should not be reset. Otherwise, as Bob pointed out, we would lose the ability to resend messages exchanged before the Logout message.