IronPort - advanced configuration guide

Chapter 2 Configuring Routing and Delivery Features
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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.
Using Global Unsubscribe
To ensure that specific recipients, recipient domains, or IP addresses never receive messages from the
Cisco IronPort appliance, use the Cisco IronPort 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.
Note 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
IronPort sales representative. Global Unsubscribe addresses can be in one of four forms:
Table 2-10 Global Unsubscribe Syntax
username@example.com Fully-formed email address
username@ Username
This syntax is used to block a specific recipient at a specific domain.
The username syntax will block all recipients with the specified
username at all domains. The syntax is the username followed by an
at sign (@).
@example.com 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 (@).
Cisco IronPort AsyncOS 7.6 for Email Advanced Configuration Guide
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