Cisco Cisco Email Security Appliance C160 ユーザーガイド
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User Guide for AsyncOS 10.0 for Cisco Email Security Appliances
Chapter 26 Configuring Routing and Delivery Features
Set Email Delivery Parameters
Possible Delivery Feature
Caution
If you enable this feature, message delivery will not be reliable and may lead to loss of messages. Also,
your appliance will not be RFC 5321-compliant. For more information, see
your appliance will not be RFC 5321-compliant. For more information, see
.
When the Possible Delivery feature is enabled, AsyncOS treats any message that times-out after the body
of the message is delivered, but before recipient host acknowledges receipt of the message, as a “possible
delivery.” This functionality prevents recipients from receiving multiple copies of a message if
continuous errors at their recipient host prevent acknowledgment of receipt. AsyncOS logs this recipient
as a possible delivery in the mail logs and counts the message as completed.
of the message is delivered, but before recipient host acknowledges receipt of the message, as a “possible
delivery.” This functionality prevents recipients from receiving multiple copies of a message if
continuous errors at their recipient host prevent acknowledgment of receipt. AsyncOS logs this recipient
as a possible delivery in the mail logs and counts the message as completed.
Default Maximum Concurrency
You also specify the default maximum number of concurrent connections the appliance makes for
outbound message delivery. (The system-wide default is 10,000 connections to separate domains.) The
limit is monitored in conjunction with the per-listener maximum outbound message delivery
concurrency (the default per listener is 600 connections for private listeners and 1000 connections for
public listeners). Setting the value lower than the default prevents the gateway from dominating weaker
networks. For example, certain firewalls do not support large numbers of connections, and this could
induce Denial of Service (DoS) warnings in these environments.
outbound message delivery. (The system-wide default is 10,000 connections to separate domains.) The
limit is monitored in conjunction with the per-listener maximum outbound message delivery
concurrency (the default per listener is 600 connections for private listeners and 1000 connections for
public listeners). Setting the value lower than the default prevents the gateway from dominating weaker
networks. For example, certain firewalls do not support large numbers of connections, and this could
induce Denial of Service (DoS) warnings in these environments.
deliveryconfig Example
In the following example, the
deliveryconfig
command is used to set the default interface to “Auto”
with “Possible Delivery” enabled. The system-wide maximum outbound message delivery is set to 9000
connections.
connections.
mail3.example.com> deliveryconfig
Choose the operation you want to perform:
- SETUP - Configure mail delivery.
[]> setup
Choose the default interface to deliver mail.
1. Auto
2. PublicNet2 (192.168.3.1/24: mail4.example.com)
3. Management (192.168.42.42/24: mail3.example.com)
4. PrivateNet (192.168.1.1/24: mail3.example.com)