Cisco Cisco Email Security Appliance C690 Mode D'Emploi
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Cisco IronPort AsyncOS 7.6 for Email Configuration Guide
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Chapter 5 Configuring the Gateway to Receive Email
In
you will use the predefined sender groups and mail flow
policies to quickly and powerfully classify the mail flowing through your gateway, enabling real-time
changes to a listener’s HAT.
changes to a listener’s HAT.
Note
The system acquires and verifies the validity of the remote host’s IP address by performing a double DNS
lookup. This consists of a reverse DNS (PTR) lookup on the IP address of the connecting host, followed
by a forward DNS (A) lookup on the results of the PTR lookup. The system then checks that the results
of the A lookup match the results of the PTR lookup. If the results do not match, or if an A record does
not exist, the system only uses the IP address to match entries in the HAT.
lookup. This consists of a reverse DNS (PTR) lookup on the IP address of the connecting host, followed
by a forward DNS (A) lookup on the results of the PTR lookup. The system then checks that the results
of the A lookup match the results of the PTR lookup. If the results do not match, or if an A record does
not exist, the system only uses the IP address to match entries in the HAT.