Troubelshooting Tip: How to troubleshoot the TACACS+ admin account user forced logged out issue on FortiDDoS-F

[kmak]

Description	This article describes how to troubleshoot the TACACS+ admin account user forced logged out issue on FortiDDoS-F.
Scope	FortiDDoS-F v7.0.X with remote authentication using TACACS+ server.
Solution	Issue Reproduction The administrator/user accounts authenticated via a remote TACACS+ server would be logged out forcefully 5 minutes after every successful log-in. The issue can be reproduced in FortiDDoS-F firmware v7.0.X. In the example, the FortiDDoS-F is configured with a TACACS+ remote authentication server. No other user was created in the FortiDDoS-F administrator page. The non-existing user will be authenticated from the TACACS+ server and check the admin-profile from the TACACS+ server. Test the user login using the TACACS+ user credential. The user would be forcefully logged out 5 minutes after the login. The FortiDDoS-F event log should be showing the login and logout history of the user. The forceful logout issue remains even after tweaking the idle timeout value. It is a bug issue on FortiDDoS-F with firmware v7.0.X. The issue is no longer seen in firmware v7.2.X, which is resolved in the version. While a workaround can be referred to as follows. Workaround: To overcome the issue without upgrading the firmware version, create the administrator/user accounts in the FortiDDoS-F for each of the TACACS+ user accounts. With the TACACS+ user account created in FortiDDoS-F, the forceful logout issue will no longer be observed. Related document: Configuring TACACS+ authentication