Cisco Cisco Email Security Appliance C160 Mode D'Emploi
Chapter 2 Configuring Routing and Delivery Features
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Cisco IronPort AsyncOS 7.1 for Email Advanced Configuration Guide
OL-22164-02
Default Delivery IP Interface
By default, the system uses an IP interface or IP interface group for email delivery.
Any currently configured IP interface or IP interface group can be set. If no
specific interface is identified, AsyncOS will use the hostname associated with
the default delivery interface in the
Any currently configured IP interface or IP interface group can be set. If no
specific interface is identified, AsyncOS will use the hostname associated with
the default delivery interface in the
SMTP HELO
command when communicating
with recipient hosts. To configure IP interfaces, use the
interfaceconfig
command.
These are the rules for using Auto selection of email delivery interfaces:
•
If the remote email server is on the same subnet as one of the configured
interfaces, then traffic will go out on the matching interface.
interfaces, then traffic will go out on the matching interface.
•
When set to auto-select, static routes you have configured using
routeconfig
take effect.
•
Otherwise, the interface that is on the same subnet as the default gateway will
be used. If all of the IP addresses have an equivalent route to the destination,
then the system uses the most efficient interface available.
be used. If all of the IP addresses have an equivalent route to the destination,
then the system uses the most efficient interface available.
Possible Delivery Feature
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 acknowledgement of receipt. AsyncOS logs
this recipient as a possible delivery in the mail logs and counts the message as
completed. It is recommended that the Possible Delivery feature remains enabled.
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 acknowledgement of receipt. AsyncOS logs
this recipient as a possible delivery in the mail logs and counts the message as
completed. It is recommended that the Possible Delivery feature remains enabled.
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 IronPort
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 IronPort