Cisco Cisco Web Security Appliance S170 사용자 가이드

You might want to configure an SMTP relay host in the following scenarios:

You want the system-generated emails to go to a non-local email address, and port 25 is blocked to 
outside networks.

Your mail servers do not allow direct port 25 traffic from internal hosts.

If no SMTP relay host is defined, AsyncOS delivers directly to the mail server for each email address.

If the Web Security appliance cannot communicate with the mail servers listed in the MX record or any 
of the configured SMTP relay hosts, it cannot send email messages and it writes a message in the log 
files. 

You can configure one or more SMTP relay hosts. You might want to configure multiple SMTP relay 
hosts for redundancy in case one system becomes unavailable. When you configure multiple SMTP relay 
hosts, AsyncOS uses the topmost available SMTP relay host. If an SMTP relay host is unavailable, it 
tries to use the one below it in the list.

You can configure the SMTP relay host from either the web interface or command line interface:

Web interface. Use the Network > Internal SMTP Relay page.

Command line interface. Use the 

smtprelay

 CLI command.

Use the Network > Internal SMTP Relay page.

To configure the SMTP relay host from the web interface:

Navigate to the Network > Internal SMTP Relay page, and click Edit Settings.

Enter the information listed in 

. 

Optionally, you can add more SMTP relay host information by clicking Add Row.

Submit and commit your changes.

Relay Hostname or IP 
Address

Enter the hostname or IP address to use for the SMTP relay

Port

Enter the port for connecting to the SMTP relay. If this property is empty, the 
appliance uses port 25. This property is optional.

Routing Table to Use 
for SMTP

Choose the routing table associated with an appliance network interface, 
either Management or Data, to use for connecting to the SMTP relay. Choose 
whichever interface is on the same network as the relay system.