hi i was trying to configure auth proxy in my router .. with acs using tacacs+.. but somewhere the authentication was failing..
i had configured acs as required and i dont find any problem with it as it is succefully working with http auth proxy..
configuration for router for telnet auth is
aaa authentication login default group aaa_serv group radius
aaa authorization auth-proxy default aaa_serv
ip auth-proxy name telnet_auth telnet
tacacs+ host 10.1.1.3 key xxxx
aaa group server tacacs+ aaa_serv
interface fastetherne 0/0
ip auth-proxy telnet_auth