Cisco Cisco Email Security Appliance C690 User Guide

If you want to perform system maintenance, the Cisco IronPort appliance should 
be placed into the offline state. The 

suspend

 and 

offline

 commands put the Cisco 

IronPort AsyncOS operating into offline state. The offline state is characterized 
by the following:

Inbound email connections are not accepted.

Outbound email delivery is halted.

Log transfers are halted.

The CLI remains accessible.

You must enter a delay for the appliance to enter the offline state. The default 
delay is thirty (30) seconds. Cisco IronPort AsyncOS allows open connections to 
complete during the delay, after which it forcefully closes open connections. If 
there are no open connections, the offline state commences immediately.

The difference between the 

suspend

 command and the 

offline

 command is that 

the 

suspend

 command retains its state even after the machine is rebooted. If you 

issue the 

suspend

 command and reboot the appliance, you must use the 

resume

 

command to return the system to an online state. 

You can use the use the System Administration > Shutdown/Suspend page in the 
GUI to suspend email receiving and delivery on the appliance. If the appliance has 
multiple listeners, you can suspend and resume email receiving on individual 
listeners. Click Commit to suspend email receiving and delivery.

 shows an Email Security appliance with suspended email receiving 

and delivery.