Cisco Cisco Email Security Appliance C160 Mode D'Emploi

See 

 for information about the 

destconfig

 command and how Virtual Gateway addresses are affected.

When you create a “group,” of Virtual Gateway addresses, the good neighbor table settings for Virtual 
Gateway are applied to the group, even if the group consists of 254 IP addresses.

For example, suppose you have created group of 254 outbound IP addresses set up as a group to cycle 
through in a “round-robin” fashion, and suppose the good neighbor table for 

small-isp.com

 is 100 

simultaneous connections for the system and 10 connections for Virtual Gateway addresses. This 
configuration will never open more than 10 connections total for all 254 IP addresses in that group; the 
group is treated as a single Virtual Gateway address.

To ensure that specific recipients, recipient domains, or IP addresses never receive messages from the 
Cisco appliance, use the Cisco AsyncOS Global Unsubscribe feature. The 

unsubscribe

 command 

allows you to add and delete addresses to a global unsubscribe list, as well as enable and disable the 
feature. AsyncOS checks all recipient addresses against a list of “globally unsubscribed” users, domains, 
email addresses, and IP addresses. If a recipient matches an address in the list, the recipient is either 
dropped or hard bounced, and the Global Unsubscribe (GUS) counter is incremented. (Log files will note 
whether a matching recipient was dropped or hard bounced.) The GUS check occurs immediately before 
an attempt to send email to a recipient, thus inspecting all messages sent by the system.

Global Unsubscribe is not intended to replace the removal of names and general maintenance of mailing 
lists. The feature is intended to act as a fail-safe mechanism to ensure email does not get delivered to 
inappropriate entities.

The global unsubscribe feature applies to private and public listeners. 

Global Unsubscribe has a maximum limit of 10,000 addresses. To increase this limit, contact your Cisco 
sales representative. Global Unsubscribe addresses can be in one of four forms:

Fully-formed email address

This syntax is used to block a specific recipient at a specific domain.

Username

The username syntax will block all recipients with the specified 
username at all domains. The syntax is the username followed by an 
at sign (

@

). 

Domain

The domain syntax is used to block all recipients destined for a 
particular domain. The syntax is the specific domain, preceded by an 
at sign (

@

).