Cisco Cisco Email Security Appliance C160 Guida Utente

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 IronPort 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 (

@

).