Resetting Message Sequence Numbers via ResetSeqNumFlag Field

The ResetSeqNumFlag (141) field in the Logon (A) the message indicates that both sides of the FIX Session should reset sequence numbers.

To send a Logon message with this flag during FIX Connection establishment, use the setResetSeqNumFlagInFirstLogon parameter of the LogonAsInitiator(string, int, int, bool, IMessage, bool) method.

Note

Some FIX venues do not support this flag.

Only the first Logon message will be sent with the ResetSeqNumFlag flag. If subsequent Logon messages are sent during the automatic attempts to restore the telecommunication link, they will be sent without this flag.

To send a Logon message with the ResetSeqNumFlag flag, each time the Logon message is sent to set this flag in the Custom Logon message.

The local incoming sequence number will be reset after counterparty replies with the confirming Logon message. If counterparty rejects the Logon message, a local incoming sequence number will still keep the old value.

If there is need to reset local sequence numbers to 1 during every logon, the ResetLocalSequenceNumbersOnLogon property should be set to true.

It is also possible to send a Logon message with the ResetSeqNumFlag set when the FIX Session is established (e.g., to maintain 24-hour connectivity) using ResetSequenceNumbersViaLogonExchange() method.