Troubleshooting Tip: GTP Error: response-hteid-doesnt-match-request

[Jackie_T]

Description	This article describes how to troubleshoot the error shown in GTP logs.
Scope	FortiOS with FortiCarrier.
Solution	The error 'response-hteid-doesn’t-match-request' means the Tunnel Endpoint Identifier in the create session respond packet does not match the TEID key in the previous create session request packet. This information can be checked by capturing the GTP packet going through FortiGate. For example, below is the Create Session Request packet in Wireshark: The TEID information can be found under the F-TEID field under the GPRS Tunneling Protocol header. Here the TEID key value is 364472207. The example below shows the response packet: On the response packet, look for the value for the Tunnel Endpoint Identifier, which is 2405939477. Hence, it does not match the value of the TEID key in the request packet and the error below will show in the GTP log: " dtlexp="response-hteid-doesnt-match-request" To resolve this error, the endpoint device that sent the response needs to be checked and ensure the Tunnel Endpoint Identifier value matches the TEID key in the request packet.