Cisco Cisco Email Security Appliance C390 사용자 가이드

Mail server accepting delayed bounce messages - Does the domain listed 
in the SMTP HELO command have MX records that resolve IP addresses for 
that domain? 

If you suspect problems with injecting email, use the following strategies:

Confirm the IP address that you are injecting from, and then use the 

listenerconfig

 command to check for allowed hosts.

Is the IP address allowed to connect to the listener you have created? Use the 

listenerconfig

 command to examine the Host Access Table (HAT) for the 

listener. Use these commands to print the HAT for a listener:

listenerconfig

 -> 

edit

 -> listener_number -> 

hostaccess

 -> 

print

 

The HAT can be configured to refuse connections by IP address, block of IP 
addresses, hostname, or domains. For more information, see “Specifying 
Hosts that are Allowed to Connect” on page 107. 

You can also use the 

limits

 subcommand to check the maximum number of 

connections allowed for a listener:

listenerconfig

 -> 

edit

 -> listener_number -> 

limits

On the machine that you are injecting from, use Telnet or FTP to manually 
connect to the appliance. For example:

injection_machine% telnet appliance_name

You can also use the 

telnet

 command within the appliance itself to connect 

from the listener to the actual appliance:

mail3.example.com> telnet

Please select which interface you want to telnet from.

1. Auto