Recently was migrating RADIUS server on Windows from one machien to another. Once new serer was ready had to reconfigure Cisco router to authenticate remote users against new RADIUS. After pointing Cisco to new RADIUS machine made a quick test to check if router can authenticate without any issues. Here is how ot do it quickly:

Successful authentication test:

R1# test aaa group radius server 192.168.1.10 username1 password1 legacy
Attempting authentication test to server-group radius using radius
User was successfully authenticated.
R1#

Unsuccessful authentication test:

R1# test aaa group radius server 192.168.1.10 username1 password1 legacy
Attempting authentication test to server-group radius using radius
User authentication request was rejected by server.
  • username1 – name of user created in AD
  • password1 – password for username1

If authentication against RADIUS was unsuccessful result will look like this: