Here only some simple information how to configure Cisco devices to use tacppd. You have to be experiencing Cisco user. If you do not clearly understand what we will do in configuration, read Cisco documentation at http://www.cisco.com.
you should setting up TACACS+ on NAS: aaa new-model aaa group server tacacs+ OUR_TACACS server your.server.ip.addr tacacs-server host your.server.ip.addr port server_port key tacacs_key
NOTE: port and key should be same as in tacppd configuration file NOTE2: "aaa group server" command can not be available. Don't care.
-for authentication add: aaa authentication login DIALUP group OUR_TACACS
-for ppp authentication: aaa authentication ppp DIALUP if-needed group OUR_TACACS
-for ppp authorization: aaa authorization network DIALUP group OUR_TACACS
-for tty commands authorization: aaa authorization exec DIALUP group OUR_TACACS
-for per-command authorization: aaa authorization commands <privilege level 1-15>
-for accounting: aaa accounting suppress null-username aaa accounting update newinfo aaa accounting network DIALUP start-stop group OUR_TACACS
-you can also use accounting periodic updates for extra users list checking: aaa accounting update periodic 1
-and configure this all on interfaces: ppp authentication chap pap DIALUP ppp authorization DIALUP ppp accounting DIALUP
-and on tty lines: authorization exec DIALUP accounting connection DIALUP login authentication DIALUP
Next thing - set up SNMP: access-list 2 permit host your_server_host snmp-server community your_community_string RW 2 BE CAREFULL - add only your tacppd host into SNMP access-list!