18 TACACS Based Authentication Support In OSM

Introduction

Terminal Access Controller Access-Control System (TACACS) refers to a family of related protocols handling remote authentication and related services for networked access control through a centralized server.

OSM NB has a plugin which can interact with TACACS server to authenticate users.

Integration

Prerequisite for Integration

• TACACS host ip address reachable from OSM.

• TACACS server secret(or password).

Integration Steps

• Configure NBI to use TACACS plugin.

  • Modifying nbi.cfg

    • Set authentication.backend as tacacs in NBI/osm_nbi/nbi.cfg

    • Set authentication.tacacs_host as TACACS host ip in NBI/osm_nbi/nbi.cfg

    • Set authentication.tacacs_secret as TACACS server secret in NBI/osm_nbi/nbi.cfg

Testing Steps

Prerequisite for Testing

• Ensure users are present in TACACS server, which can be used for authentication.

• Configure OSM as mentioned above.

Testing

• Login with credentials present in TACACS server.

• OSM User with system_admin role or similar can assign project role mapping.

• TACACS users can log in using their credentials.

Limitations

• Since TACACS is used as read-only service, username update and password update shall not be allowed via OSM. User credentials need to be updated by TACACS admin in TACACS to reflect. However, OSM admin can handle project role assignment as required.

• If user profile is removed from TACACS server, OSM still maintains the profile and will not be removed until next login. As the profile is not available in TACACS, the authentication shall fail and user profile will be removed from OSM.