Cisco Cisco Email Security Appliance C650 Guía Del Usuario
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Cisco IronPort AsyncOS 7.5 for Email Advanced Configuration Guide
OL-25137-01
Chapter 2 Configuring Routing and Delivery Features
Overview: Tagging and IronPort Bounce Verification
When sending email with bounce verification enabled, your IronPort appliance
will rewrite the Envelope Sender address in the message. For example, MAIL
FROM:
will rewrite the Envelope Sender address in the message. For example, MAIL
FROM:
joe@example.com
becomes MAIL FROM:
prvs=joe=123ABCDEFG@example.com
. The
123...
string in the example is the
“bounce verification tag” that gets added to the Envelope Sender as it is sent by
your IronPort appliance. The tag is generated using a key defined in the Bounce
Verification settings (see
your IronPort appliance. The tag is generated using a key defined in the Bounce
Verification settings (see
for more information about specifying a key). If this message bounces,
the Envelope Recipient address in the bounce will typically include this bounce
verification tag.
verification tag.
You can enable or disable bounce verification tagging system-wide as a default.
You can also enable or disable bounce verification tagging for specific domains.
In most situations, you would enable it by default, and then list specific domains
to exclude in the Destination Controls table (see
You can also enable or disable bounce verification tagging for specific domains.
In most situations, you would enable it by default, and then list specific domains
to exclude in the Destination Controls table (see
).
If a message already contains a tagged address, AsyncOS does not add another tag
(in the case of an IronPort appliance delivering a bounce message to an IronPort
appliance inside the DMZ).
(in the case of an IronPort appliance delivering a bounce message to an IronPort
appliance inside the DMZ).
Handling Incoming Bounce Messages
Bounces that include a valid tag are delivered. The tag is removed and the
Envelope Recipient is restored. This occurs immediately after the Domain Map
step in the email pipeline. You can define how your IronPort appliances handle
untagged or invalidly tagged bounces — reject them or add a custom header. See
Envelope Recipient is restored. This occurs immediately after the Domain Map
step in the email pipeline. You can define how your IronPort appliances handle
untagged or invalidly tagged bounces — reject them or add a custom header. See
for more
information.
If the bounce verification tag is not present, or if the key used to generate the tag
has changed, or if the message is more than seven days old, the message is treated
as per the settings defined for IronPort Bounce Verification.
has changed, or if the message is more than seven days old, the message is treated
as per the settings defined for IronPort Bounce Verification.