Enable TACACS+ authentication

aaa-server TAC12 protocol tacacs+
aaa-server TAC12 (management) host 10.166.67.4
 key *****
aaa-server TAC12 (management) host 10.11.16.10
 key *****

aaa authentication http console TAC12 LOCAL
aaa authentication ssh console TAC12 LOCAL
aaa authentication serial console TAC12 LOCAL
aaa accounting ssh console TAC12
aaa accounting serial console TAC12
aaa accounting enable console TAC12
aaa accounting command TAC12

policy-map global_policy
 class class-default
  user-statistics accounting