Cisco Cisco Email Security Appliance C650 Guía Del Usuario
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Cisco AsyncOS 9.1 for Email User Guide
Chapter 24 Configuring Routing and Delivery Features
Controlling Email Delivery Using Destination Controls
Controlling the Number of Connections, Messages, and Recipients to a Domain
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.
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
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.
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.)
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.)
for the entire domain. (Many domains have multiple MX records defined for accepting email.)
Note
The current system default is 500 connections per domain and 50 messages per connection.
These values are explained in
.
Table 24-8
Values in the Destination Controls Table
Field
Description
Concurrent
Connections
Connections
The maximum number of outbound connections that will be made by the appliance to
a given host. (Note that the domain can include your internal groupware hosts.)
a given host. (Note that the domain can include your internal groupware hosts.)
Maximum
Messages Per
Connection
Messages Per
Connection
The maximum number of messages allowed for a single outbound connection from the
appliance to a given host before initiating a new connection.
appliance to a given host before initiating a new connection.
Recipients
The maximum number of recipients allowed within the given period of time. “None”
denotes that there is no recipient limit for the given domain.
denotes that there is no recipient limit for the given domain.
The minimum period of time — between 1 and 60 minutes — that the appliance will
count the number of recipients. Specifying a time period of “0” disables the feature.
count the number of recipients. Specifying a time period of “0” disables the feature.
Note
If you change the recipient limit, AsyncOS resets the counters for all messages
already in the queue. The appliance delivers the messages based on the new
recipient limit.
already in the queue. The appliance delivers the messages based on the new
recipient limit.