Cisco ASA 5505 - Manual (Page 1345)

63-21
Cisco ASA 5500 Series Configuration Guide using the CLI
Chapter 63 Configuring Active/Active Failover
Remote Command Execution
3. Normally the return traffic would be dropped because there is no session information for the traffic
on interface 192.168.2.2. However, the interface is configured with the command asr-group 1. The
unit looks for the session on any other interface configured with the same ASR group ID.
4. The session information is found on interface outsideISP-A (192.168.1.2), which is in the standby
state on the unit SecAppB. Stateful Failover replicated the session information from SecAppA to
SecAppB.
5. Instead of being dropped, the layer 2 header is rewritten with information for interface 192.168.1.1
and the traffic is redirected out of the interface 192.168.1.2, where it can then return through the
interface on the unit from which it originated (192.168.1.1 on SecAppA). This forwarding continues
as needed until the session ends.
Remote Command Execution
Remote command execution lets you send commands entered at the command line to a specific failover
peer.
Because configuration commands are replicated from the active unit or context to the standby unit or
context, you can use the failover exec command to enter configuration commands on the correct unit,
no matter which unit you are logged in to. For example, if you are logged in to the standby unit, you can
use the failover exec active command to send configuration changes to the active unit. Those changes
are then replicated to the standby unit. Do not use the failover exec command to send configuration
commands to the standby unit or context; those configuration changes are not replicated to the active
unit and the two configurations will no longer be synchronized.
Output from configuration, exec, and show commands is displayed in the current terminal session, so
you can use the failover exec command to issue show commands on a peer unit and view the results in
the current terminal.
You must have sufficient privileges to execute a command on the local unit to execute the command on
the peer unit.
To send a command to a failover peer, perform the following steps:
Step 1 If you are in multiple context mode, use the changeto command to change to the context you want to
configure. You cannot change contexts on the failover peer with the failover exec command.
If you are in single context mode, skip to the next step.
Step 2 Use the following command to send commands to he specified failover unit:
hostname(config)# failover exec {active | mate | standby}
Use the active or standby keyword to cause the command to be executed on the specified unit, even if
that unit is the current unit. Use the mate keyword to cause the command to be executed on the failover
peer.
Commands that cause a command mode change do not change the prompt for the current session. You
must use the show failover exec command to display the command mode the command is executed in.
See
Changing Command Modes, page 63-22 , for more information.