Connection your Cisco routers and switches to the AAA RADIUS server.

  • AAA stands for Authentication, Authorization, and Accounting.
  • RADIUS is a distributed client/server authentication system.
  • TACACS+ is a protocol developed by Cisco for Terminal Access Control.

AAA uses RADIUS or TACACS+ to verify credentials on a server when a user is trying to log in.

On all network devices (routers, switches, access points, etc) issue the following commands:

enable
configure terminal

enable secret LOCAL_PASSWORD
username admin privilege 15 secret ADMIN_PASSWORD

Note: you just created local credentials in case the RADIUS or TACACS+ is not reachable it will fall back to the local database.

For RADIUS

aaa new-model
aaa authentication enable default group radius local
aaa authentication login default group radius local
aaa authorization exec default group radius local
radius-server host 192.168.1.100 key PASSWORD

For TACACS+

aaa new-model
aaa authentication enable default group tacacs+ local
aaa authentication login default group tacacs+ local
aaa authorization exec default group tacacs+ local
tacacs-server host 192.168.1.100 key PASSWORD

Replace the IP 192.168.1.100 and the PASSWORD with the information of the RADIUS or TACACS+ server.

Test if the AAA is successfully authenticating through using the server:

do test aaa group radius REMOTE_USER REMOTE_PASSWORD new-code

OR

do test aaa group tacacs+ REMOTE_USER REMOTE_PASSWORD legacy

Note that REMOTE_USER REMOTE_PASSWORD has to be already created on the server.

Other useful commands:

show users
do debug aaa authentication
do debug radius
do debug tacacs