Cisco Cisco Email Security Appliance C160 Mode D'Emploi

Each outbound destination domain has its own outbound queue. Therefore, each domain has a separate 
set of concurrency limits as specified in the Destination Controls table. Further, each unique domain not 
listed specifically in the Destination Controls table uses another set of the “Default” limits as set in the 
table.

Use the Mail Policies > Destination Controls page in the GUI or the 

destconfig

 command in the CLI to 

create, edit, and delete Destination Control entries.

You can configure which version of Internet Protocol addresses to use for the connection to a domain. 
The Email Security appliance uses both Internet Protocol version 4 (IPv4) and Internet Protocol version 
(IPv6). You can configure a listener on the appliance to use one version of the protocol or both.

If the “Required” setting for either IPv4 or IPv6 is specified, the appliance will negotation a connection 
to the domain using an address of the specified version. If the domain doesn’t use that IP address version, 
no email will be sent. If the “Preferred” setting for either IPv4 or IPv6 is specified, the appliance will 
first attempt to negotation a connection to the domain using an address of the specified version then fall 
back to the other if the first is not reachable.

You may want to limit how your appliance will deliver email to avoid overwhelming remote hosts or your 
own internal groupware servers with email from your appliance. 

For each domain, you can assign a maximum number of connections, outbound messages, and recipients 
that will never be exceeded by the system in a given time period. This “good neighbor” table is defined 
through the Destination Controls feature (Mail Policies > Destination Controls or the 

destconfig

 

command — previously the 

setgoodtable

 command). You can specify the domain name using the 

following syntax: 

domain.com

or

.domain.com

This syntax enables AsyncOS to specify destination controls for sub-domains such as 
sample.server.domain.com without entering each full subdomain address individually.

For connections, messages, and recipients, you set whether the limits you define are enforced for each 
Virtual Gateway address, or for the entire system. (Virtual Gateway address limits control the number of 
concurrent connections per IP interface. System-wide limits control the total number of connections the 
appliance will allow.) 

You also set whether the limits you define are enforced for each MX record of the specified domain, or 
for the entire domain. (Many domains have multiple MX records defined for accepting email.) 

The current system default is 500 connections per domain and 50 messages per connection.