Imported from previous forum
Should the MsgSeqNum be bumped up on an unsuccessful logon? Or should it only be bumped on a successful logon?
PLEASE ADVISE!!!
[ original email was from John Prewett - jprewett@lavatrading.com ]
Hi Maura,
I am assuming that you are discussing the behavior for the FIX Acceptor when handling an invalid Logon attempt.
Here is an excerpt taken from the "SessionProtocol" section of Volume 2 of the current FIX.4.2 specification with errata:
<start of quote>
If authentication fails, the session acceptor should shut down the connection after optionally sending a Logout message to indicate the reason of failure. Sending a Logout in this case is not required because doing so would consume a sequence number for that session, which in some cases may be problematic.
<end of quote>
So it’s basically your choice.
If you believe the logon attempt was from the correct initiator but some of the fields weren’t acceptable, send a Logout, incrementing the sequence number and disconnect.
On the other hand, if you think it is possible that it may not even be the correct initiator at all such that using a sequence number could potentially cause problems when the real initiator decides to connect, just disconnect without sending any message.
If you are in doubt as to which strategy to use under certain circumstances, just disconnect - better safe than sorry.
I hope this helps.
> Should the MsgSeqNum be bumped up on an unsuccessful logon? Or should it only be bumped on a successful logon?
>
> PLEASE ADVISE!!!
>
>
[ original email was from Himanshu Sharma - hsharma@knighttrading.com ]
I prefer to bump-up MsgSeqNum on every outgoing msg (except Resent msg, etc). It is safe and avoids confusion for both parties when they check logs and see msg with same MsgSeqNum.
> Should the MsgSeqNum be bumped up on an unsuccessful logon? Or should it only be bumped on a successful logon?
>
> PLEASE ADVISE!!!
>
>