AAAGlobal Config

aaa accounting exec default start-stop group tacacs+

Enables AAA accounting for all EXEC shell sessions (user login/logout) and sends accounting records to a TACACS+ server group for auditing or billing.

Syntax·Global Config
aaa accounting exec default start-stop group tacacs+

When to Use This Command

  • Track user login and logout times for security auditing in a corporate network.
  • Generate billing records for customer access to a managed router or switch.
  • Comply with regulatory requirements by logging all administrative access to network devices.
  • Monitor failed login attempts by combining with login authentication failure accounting.

Command Examples

Basic AAA Accounting for EXEC Sessions

aaa accounting exec default start-stop group tacacs+
Router(config)# aaa accounting exec default start-stop group tacacs+
Router(config)#

No output is displayed upon successful configuration. The command enables accounting for all EXEC sessions using the default method list, with start-stop logging to the TACACS+ server group.

Verifying AAA Accounting Configuration

show aaa accounting
AAA Accounting method lists:
  exec        default    start-stop group tacacs+
  commands    default    stop-only group tacacs+
  connection  default    start-stop group tacacs+
  network     default    start-stop group tacacs+
  system      default    start-stop group tacacs+
  resource    default    stop-only group tacacs+

The output lists all configured accounting method lists. The 'exec' line shows that EXEC accounting uses the default list with start-stop mode and TACACS+ group. Other lines show additional accounting types if configured.

Understanding the Output

The 'show aaa accounting' command displays the configured accounting method lists. Each line corresponds to a type of accounting (exec, commands, connection, network, system, resource). The 'default' keyword indicates the method list name. The mode (start-stop, stop-only, wait-start) defines when records are sent. 'group tacacs+' specifies the server group. In a real network, you would verify that the correct accounting type is present and that the server group matches your TACACS+ configuration. If no output appears for a type, accounting is not enabled for that activity. Good configuration shows all desired types with correct mode and group. Watch for missing types or incorrect group names that could cause accounting failures.

CCNA Exam Tips

1.

CCNA exam tip: The 'default' in 'aaa accounting exec default' is the method list name, not a keyword; you can create custom lists like 'aaa accounting exec MYLIST start-stop group tacacs+'.

2.

CCNA exam tip: 'start-stop' sends a 'start' record when the session begins and a 'stop' record when it ends; 'stop-only' sends only a stop record; 'wait-start' delays access until the start record is acknowledged.

3.

CCNA exam tip: AAA accounting does not affect authentication or authorization; it only logs activity. You must also configure 'aaa authentication login' and 'aaa authorization exec' for full AAA.

4.

CCNA exam tip: The TACACS+ server must be reachable and configured with 'tacacs-server host' and 'key' commands, otherwise accounting records will not be sent.

Common Mistakes

Mistake 1: Forgetting to configure the TACACS+ server with 'tacacs-server host' and 'key', causing accounting records to fail silently.

Mistake 2: Using 'stop-only' instead of 'start-stop' when you need both login and logout records, missing the start event.

Mistake 3: Applying the command without also enabling 'aaa new-model', which is required for all AAA commands to take effect.

Related Commands

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