Reason and diagnostic network codes

Reason codes: REASON codes provide a general explanation of the error detected, or the refusal.

Diagnostic codes: DIAGNOSTIC (diag) codes provide a detailed explanation of the source of the error detected or the refusal.

TCP/IP network codes

TCP/IP reason codes

REASON corresponds to the reason code returned by the TCP/IP communication system.

The codes are expressed in hexadecimal.

TCP/IP Reason codes

Code Description


Connection request rejected by the network or break caused by the remote partner


Time-out for a connection request. The called party is probably not connected to the network.


Insufficient resources (other than memory)


Insufficient memory


The network access point reference passed to the connection is not valid


Invalid parameter in TCP request sent


Other cause of rejection


Invalid local or remote address

TCP/IP diagnostic codes

DIAGN (TCP/IP diagnostic codes) corresponds to the diagnostic code returned by the TCP/IP communication system.

The value of this code corresponds to the "errno" variable provided by the TCP/IP resource. In this case, refer to the manufacturer's documentation for the meaning of this code.

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