How to Configure TACACS+ Support on the Cache Engine

Introduction

This document describes how to configure Terminal Access Controller Access Control System Plus (TACACS+) support in order to access the Cisco Cache Engine. The instructions in this document allow you to validate against a remote TACACS+ server/database when you telnet to the Cache Engine. If the server does not include an entry for your user ID, it checks locally for valid access information.

Prerequisites

Requirements

There are no specific requirements for this document.

Components Used

The information in this document is based on these software and hardware versions:

• Cisco Cache Engine 505 in a lab environment with cleared configurations

• Cisco Cache Engine Software Release 2.3.1

• CiscoSecure for UNIX

The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, make sure that you understand the potential impact of any command.

Conventions

Refer to the Cisco Technical Tips Conventions for information on document conventions.

Configure

In this section, you are presented with the information to configure the features described in this document.

Note: Use the Command Lookup Tool (registered customers only) to obtain more information on the commands used in this section.

Network Diagram

This document uses this network setup:

Configure the Cache Engine for TACACS+ Support

Complete these steps in order to configure the Cache Engine for TACACS+ support:

1. Configure the Cache Engine for the respective version of Web Cache Communication Protocol (WCCP).

2. Use these commands for the default configuration:

   authentication login local enable
   authentication configuration local enable
   

3. Configure the TACACS+ server IP address. If multiple servers specify which address is primary, then the secondary servers are left as blank options.

4. Configure authentication to the TACACS+ server as primary. If the server is not available, then the default will be the locally specified authentication.

5. Configure authentication to the TACACS+ key information where necessary.

Note: You must enable TACACS+ on the Cisco Cache Engine because Cisco Cache Engines use PPP in order to authenticate with the TACACS server, unlike the routers that do not require PPP. In order to enable TACACS+ on Cisco Cache Engines, open Cisco Secure ACS 2.6, click the Group Setup tab, and check the PPP IP check box located in the TACACS+ Settings area.

Your command lines should appear similar to this output:

cepro(config)#tacacs server 172.18.124.114
cepro(config)#authentication login tacacs ena primary
cepro(config)#authen configuration tacacs enab

Verify

Use this section to confirm that your configuration works properly.

The Output Interpreter Tool (registered customers only) (OIT) supports certain show commands. Use the OIT to view an analysis of show command output.

• show version—Displays the software that runs on the Cache Engine, as well as some other components as the system uptime (such as where the code was previously booted and the date when it was compiled).

  cepro#show version
  Cisco Cache Engine
  Copyright (c) 1986-2001 by Cisco Systems, Inc.
  Software Release: CE ver 2.31 (Build: FCS  02/16/01)
  Compiled: 11:20:14 Feb 22 2001 by bbalagot
  Image text-base 0x108000, data_base 0x437534
  
  System restarted by Reload
  The system has been up for 20 hours, 42 minutes, 59 seconds.
  System booted from "flash"

• show hardware—Displays the same information as the show version command, as well as the hardware components of the Cache Engine.

  cepro#show hardware
  Cisco Cache Engine
  Copyright (c) 1986-2001 by Cisco Systems, Inc.
  Software Release: CE ver 2.31 (Build: FCS  02/16/01)
  Compiled: 11:20:14 Feb 22 2001 by bbalagot
  Image text-base 0x108000, data_base 0x437534
  
  System restarted by Reload
  The system has been up for 21 hours, 15 minutes, 16 seconds.
  System booted from "flash"
  
  Cisco Cache Engine CE505 with CPU AMD-K6 (model 8) (rev. 12) AuthenticAMD
  2 Ethernet/IEEE 802.3 interfaces
  1 Console interface.
  134213632 bytes of Physical Memory
  131072 bytes of ROM memory.
  8388608 bytes of flash memory.
  
  List of disk drives:
       /c0t0d0  (scsi bus 0, unit 0, lun 0)

• show running-config—Displays the running configuration on the Cache Engine.

  cepro#show running-config
  
  Building configuration...
  Current configuration:
  !
  !
  !
  user add admin uid 0  password 1 "eeSdy9dcy"  capability admin-access
  user add chbanks uid 5001  password 1 "eeSdy9dcy"  capability admin-access
  !
  !
  !
  hostname cepro
  !
  interface ethernet 0
   ip address 10.27.2.2 255.255.255.0
   ip broadcast-address 10.27.2.255
  exit
  !
  !
  interface ethernet 1
  exit
  !
  ip default-gateway 10.27.2.1
  ip route 0.0.0.0 0.0.0.0 10.27.2.1
  cron file /local/etc/crontab
  !
  wccp router-list 1 10.27.2.1
  wccp web-cache router-list-num 1
  !
  authentication login tacacs enable primary
  authentication login local enable !--- on by default ---!
  authentication configuration tacacs enable
  authentication configuration local enable  !---- on by default ---!
  tacacs server 172.18.124.114 primary
  rule no-cache url-regex .*cgi-bin.*
  rule no-cache url-regex .*aw-cgi.*
  !
  !
  end
  cepro#
  

• show tacacs —Displays the settings for the TACACS+ server.

  cepro#show tacacs
      Login Authentication for Console/Telnet Session: enabled (primary)
      Configuration Authentication for Console/Telnet Session: enabled
  
      TACACS Configuration:
      ---------------------
      Key        =
      Timeout    = 5 seconds
      Retransmit = 2 times
  
      Server                         Status
      ----------------------------   ------
      172.18.124.114                 primary
  

• show statistics tacacs—Displays TACACS+ statistics.

  cepro#show statistics tacacs
      TACACS+ Statistics
      -----------------
      Number of access requests: 13
      Number of access deny responses: 7
      Number of access allow responses: 0
  

• show authentication—Displays the current TACACS+ current authentication and authorization configuration.

  cepro#show authentication
  Login Authentication:         Console/Telnet Session
  ----------------------------- -----------------------
  local                         enabled
  tacacs                        enabled (primary)
  
  Configuration Authentication: Console/Telnet Session
  ----------------------------- -----------------------
  local                         enabled
  tacacs                        enabled
  
  cepro#

Troubleshooting Commands

This section provides information you can use to troubleshoot your configuration.

The Output Interpreter Tool (registered customers only) (OIT) supports certain show commands. Use the OIT to view an analysis of show command output.

Note: Refer to Important Information on Debug Commands before you use debug commands.

• show debug—Displays the debug commands that are enabled.

  cepro#show debug
  Authentication debugging is on
  Tacacs debugging is on
  

• terminal monitor —Displays the outputs of debugs to the screen. This output displays the results of the debug authentication and debug tacacs commands.

  cepro#terminal monitor
  cepro#authenticateUser(): Begin
  setRemoteIPAddress(): pRemoteAddress 172.18.124.193
  bAuthentication(): Begin
  bAuthenticationIntersection(): Begin
  bAuthenticationIntersection(): telnet_access 1
  setAuthenticatedService(): nServiceToAuthenticate 6
  getAuthenticatedService(): Begin
  getAuthenticatedService(): nServiceToAuthenticate = 6
  bAuthenticationIntersection() getAuthenticatedService 6
  setErrorDisplayed(): Begin bStatus 0
  getLocalLoginAuthEnable(): Begin
  getLocalLoginAuthEnable(): uiState = 1
  getTacacsLoginAuthEnable(): Begin
  getTacacsLoginAuthEnable(): uiState = 1
  getTacacsLoginAuthPrimary(): Begin
  getTacacsLoginAuthPrimary(): uiState = 1
  IncrementTacacsStatRequest(): Begin
  tacacs_plus_login() Begin
  isConsole() Begin
  getAuthenticatedService(): Begin
  getAuthenticatedService(): nServiceToAuthenticate = 6
  isConsole() nReturn 0 telnet
  tacacs_plus_login() sWhatService() tty = telnet
  getRemoteIPAddress(): Begin
  getRemoteIPAddress(): pRemoteAddress = 172.18.124.193
  tacacs_plus_login() getRemoteIPAddress sHostIp 172.18.124.193
  tacacs_malloc() Begin 164
  tacacs_malloc() PSkmalloc ptr
  getUserStruct() malloc_named ustr
  tacacs_plus_login() allocated memory for ustruct
  aaa_update_user() Begin
  debug_authen_svc() Begin
  
  aaa_update_user(): user='admin' ruser='system' port='telnet' 
      rem_addr='172.18.124.193' authen_type=1
  tacacs_plus_login() updated user
  getNumTacacsLoginAttempts(): Begin
  getNumTacacsLoginAttempts(): ulRetransmit = 2
  ####### tacacs_plus_login() num_tries 1
  aaa_start_login() Begin
  debug_start_login() Begin
  
  debug_start_login()/AUTHEN/START (0): port='telnet' list='(null)' 
      action=LOGIN service=LOGIN
  aaa_randomize_id() Begin
  tacacs_plus_start_login() Begin
  tacacs_parse_server() Begin user_str admin
  getTacacsDirectRequestEnable(): Begin
  getTacacsDirectRequestEnable(): cDirectRequestEnable = 0
  printIpAddr() Begin
  printIpAddr() 0.0.0.0
  tacacs_plus_start_login() server.ip_addr 0.0.0.0          server.type 
      0 server.length 0
  choose_version() Begin
  create_authen_start() Begin
  create_authen_start() len 45
  tacacs_malloc() Begin 45
  tacacs_malloc() PSkmalloc ptr
  create_authen_start() malloc_named tac_pak
  fill_tacacs_plus_hdr() Begin encrypt 1
  fill_tacacs_plus_hdr() len 33, tac_pak->length 33
  #### fill_tacacs_plus_hdr() tac_pak->encrypted 1
  #### fill_tacacs_plus_hdr() TEST nTestLen 33
  create_authen_start() len 33, tac_pak->length 33
  create_authen_start() u->priv_lvl  15 start->priv_lvl 15
  create_authen_start() start->action 1
  create_authen_start() start->authen_type 1
  create_authen_start() start->service 1
  create_authen_start() user_len 5
  create_authen_start() port_len 6
  create_authen_start() addr_len 14
  create_authen_start() out_len 33
  tacacs_plus_start_login() TACACS+: send AUTHEN/START packet ver=192 
      id=1541646967
  tacacs_plus_start_login() login to TACACS+ server:
  printIpAddr() Begin
  printIpAddr() 0.0.0.0
  tacacs_plus_get_conn() Begin server(0)
  printIpAddr() Begin
  printIpAddr() 0.0.0.0
  tacacs_plus_get_conn() **pSocketHandleIndex 89434348
  tacacs_plus_get_conn() Look at server in the TACACS+ server list
  tacacs_plus_get_conn() TACACS+: This is a loop through server list
  tacacs_plus_openconn() Begin
  printIpAddr() Begin
  printIpAddr() 172.18.124.114
  open_handle() Begin
  tacacs_plus_socket() Begin
  tacacs_plus_socket Socket: return nSocket 784 nSockFdTbl[28] = 784
  printIpAddr() Begin
  printIpAddr() 172.18.124.114
  open_handle() TACACS+: Opening TCP/IP connection to 172.18.124.114
  open_handle() nSockFdTbl[28]= 784
  setCurrentServer() Begin SaveCurrentServer->ip_addr 172.18.124.114
  IncrementTacacsStatPerServerRequest(): Begin
  ##### IncrementTacacsStatPerServerRequest  Server->ip_addr 1920733868 
      tacacs_root.ulTacacsServerAddr
  open_handle() socket(28) 784
  tacacs_plus_connect() Begin
  tacacs_plus_connect() socket(28) 784
  tacacs_plus_connect() End
  open_handle() is connected
  open_handle() *connection_handle 28
  open_handle() **pSocketHandleIndex 28
  tacacs_plus_openconn() **pSocketHandleIndex 28
  get_server() Begin
  tacacs_plus_openconn() server->opens++
  tacacs_plus_get_conn() **pSocketHandleIndex 28
  tacacs_plus_get_conn() oldServerCount: 0, count:0
   tacacs_plus_start_login() **pHandleIndex 28
  tacacs_plus_send_receive() Begin
  tacacs_plus_proc_send_receive() Begin
  tacacs_plus_proc_send_receive() length 33
  copy_tac_plus_packet() Begin
  tacacs_malloc() Begin 45
  tacacs_malloc() PSkmalloc ptr
  copy_tac_plus_packet() malloc_named copy
  tacacs_plus_encrypt() Begin
  getTacacsKey(): Begin
  getTacacsKey(): sKey =
  tacacs_plus_encrypt() key
  tacacs_plus_encrypt() sizeof(tacacs_plus_pkt_hdr) 12
  tacacs_plus_encrypt() sizeof(uchar) 1
  tacacs_plus_encrypt() tac_pak->encrypted 1
  tacacs_plus_encrypt() tac_pak->encrypted = TAC_PLUS_CLEAR && key is empty
  tacacs_plus_proc_send_receive() out_pak->encrypted 1
  tacacs_plus_proc_send_receive() out_pak->encrypted 1
  tacacs_plus_proc_send_receive() PSkfree dump_pak
  tacacs_plus_proc_send_receive() ntohl(out_pak->length) 33
  dump_start_session() Begin ntohl(out_pak->length) 33
  getTacacsKey(): Begin
  getTacacsKey(): sKey =
  0xc0 0x1 0x1 0x1 0x77 0xaa 0xe3 0x5b 0x0 0x0 0x0 0x21 0x1 0xf 0x1 0x1 0x5 
       0x6 0xe 0x0 0x61 0x64 0x6d
  encrypt_md5_xor() Begin
  encrypt_md5_xor() no key
  dump_summarise_incoming_packet_type() Begin
  Read AUTHEN/START size=45
  dump_nas_pak() Begin
  dump_header() Begin
  PACKET: key=
  version 192 (0xc0), type 1, seq no 1, encrypted 1
  session_id 2007688027 (0x77aae35b), Data length 33 (0x21)
  End header
  type=AUTHEN/START, priv_lvl = 15action=login
  authen_type=ascii
  service=login
  user_len=5 port_len=6 (0x6), rem_addr_len=14 (0xe)
  data_len=0
  User: port: rem_addr: data:
  End packet
  dump_start_session() PSkfree test
  getTacacsTimeout(): Begin
  getTacacsTimeout(): ulTimeout = 5
  tacacs_plus_sockwrite() Begin
  tacacs_plus_proc_send_receive() PSkfree out_pak
  getTacacsTimeout(): Begin
  getTacacsTimeout(): ulTimeout = 5
  sockread() Begin
  tacacs_plus_proc_send_receive() read
  tacacs_malloc() Begin 18
  tacacs_malloc() PSkmalloc ptr
  tacacs_plus_proc_send_receive() malloc_named *in
  tacacs_plus_proc_send_receive() allocated memory
  getTacacsTimeout(): Begin
  getTacacsTimeout(): ulTimeout = 5
  sockread() Begin
  tacacs_plus_proc_send_receive() OK
  tacacs_plus_decrypt() Begin
  getTacacsKey(): Begin
  getTacacsKey(): sKey =
  tacacs_plus_decrypt() key
  tacacs_plus_decrypt() tac_pak->encrypted = TAC_PLUS_CLEAR && key is empty
  authen_resp_sanity_check() Begin
  tacacs_plus_hdr_sanity_check() Begin
  authen_debug_response() Begin
  authen_debug_response() TACACS+: ver=192 id=1541646967 received AUTHEN 
      status = FAIL
  tacacs_plus_start_login() PSkfree out_tac_pak
  unload_authen_resp() Begin
  tacacs_plus_start_login() PSkfree in_tac_pak
  debug_authen_status() Begin
  
  TACACS+/AUTHEN (2007688027): status = FAIL
  
  tacacs_plus_login() Authentication failed.
  tacacs_plus_login() label1
  aaa_cleanup_login() Begin
  aaa_close_connection() Begin
  tacacs_plus_closeconn() Begin
  get_server() Begin
  close_handle() Begin
  close_handle() nHandleIndex 28 nSockFdTbl[**handle] 784
  aaa_set_password() Begin
  aaa_free_user() Begin
  debug_authen_svc() Begin
  aaa_close_connection() Begin
  
  TACACS+/AUTHEN: free user admin system telnet 172.18.124.193 
      authen_type=ASCII service=LOGIN priv_lv
  aaa_free_user() PSkfree ustr
  ####### tacacs_plus_login() num_tries 2
  aaa_start_login() Begin
  debug_start_login() Begin
  
  debug_start_login()/AUTHEN/START (0): port='unknown' list='(null)' 
      action=LOGIN service=LOGIN
  
  TACACS+/AUTHEN/START aaa_start_login() (0): ERROR (no ustruct)
      tacacs_plus_login() TACACS+: aaa_start
  aaa_free_user() Begin
  tacacs_plus_login() try_local_login AUTHENTICATION_INTERNAL_ERROR
  IncrementTacacsStatDenyAccess(): Begin
  localAuthentication(): Begin
  localAuthentication() usrName admin
  localAuthentication() passwd system
  localAuthentication() pUid 89435294
  localAuthentication() telnet_access
  localAuthentication() rc == TRUE
  AuthenticationIntersection(): bTacacsLogin 0
  IncrementLocalLoginStat(): Begin
  getLocalConfigAuthEnable(): Begin
  getLocalConfigAuthEnable(): uiState = 1
  getTacacsConfigAuthEnable(): Begin
  getTacacsConfigAuthEnable(): uiState = 1
  getTacacsConfigAuthPrimary(): Begin
  getTacacsConfigAuthPrimary(): uiState = 0
  localAuthentication(): Begin
  localAuthentication() usrName admin
  localAuthentication() passwd system
  localAuthentication() pUid 89435294
  localAuthentication() telnet_access
  localAuthentication() rc == TRUE
  AuthenticationIntersection(): bTacacsConfig 0
  AuthenticationIntersection():== Local Database Authentication ==
  IncrementLocalConfigStat(): Begin
  AuthenticationIntersection(): user has been found
  AuthenticationIntersection(): bTacacsLogin pUid 89435294
  AuthenticationIntersection(): GOT ACCESS capab 0 Admin 0 Ftp 0 Http 0 
      Telnet 0
  
  authenticateUser() AUTHENTICATION IS OK
  authenticateUser() AUTHENTICATION #2
  

Related Information

• Cisco 500 Series Cache Engine Products & Services