| Description | This article describes how to investigate if the reason for the empty return code could be related to a fail in the TLS negotiation. |
| Scope | FortiWeb v7.4.x. |
| Solution |
The empty return code could be interpreted as no response from the server:
In some scenarios the cause is related to TLS negotiation is not completing between FortiWeb and the real server because of a TLS version. A packet capture between Fortiweb and the real server could help to see this error:
Confirm with the real server administrator what version the real server supports and enable the specific version of TLS in the server pool configuration. Go to Server Objects- > Server -> Server Pool -> SSL Connection Settings and adjust the TLS versions supported by the real server.
Note: There is an empty return code because of the TLS negotiation failure. This could be one of several reasons why FortiWeb shows the status empty code. Open a TAC ticket in case to further investigation in case the TLS negotiation is completed.
For an explanation of the mechanism of FortiWeb traffic log, including the meaning of response code 0, see the related article Technical Tip: Response Code 0 found in Traffic Log |
