Security | 915Suppress AAA Accounting for null username sessionsWhen AAA Accounting is activated, the FTOS software issues accounting records for all users on thesystem, including users whose username string, because of protocol translation, is NULL. An example ofthis is a user who comes in on a line where the AAA Authentication login method-list none command isapplied. To prevent accounting records from being generated for sessions that do not have usernamesassociated with them, perform the following task in CONFIGURATION mode:Configure Accounting of EXEC and privilege-level command usageThe network access server monitors the accounting functions defined in the TACACS+ attribute/value(AV) pairs.In the following sample configuration, AAA accounting is set to track all usage of EXEC commands andcommands on privilege level 15.System accounting can use only the default method list:aaa accounting system default start-stop tacacs+Configure AAA Accounting for terminal linesUse the following commands to enable accounting with a named method list for a specific terminal line(where com15 and execAcct are the method list names):Monitor AAA AccountingFTOS does not support periodic interim accounting, because the periodic command can cause heavycongestion when many users are logged in to the network.Command Syntax Command Mode Purposeaaa accounting suppressnull-usernameCONFIGURATION Prevent accounting records from being generated forusers whose username string is NULLFTOS(conf)#aaa accounting exec default start-stop tacacs+FTOS(conf)#aaa accounting command 15 default start-stop tacacs+FTOS(config-line-vty)# accounting commands 15 com15FTOS(config-line-vty)# accounting exec execAcct
