Cisco Cisco Email Security Appliance C160 Mode D'Emploi
C H A P T E R
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User Guide for AsyncOS 9.7 for Cisco Email Security Appliances
5
Configuring the Gateway to Receive Email
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Overview of Configuring the Gateway to Receive Email
The appliance functions as the email gateway for your organization, servicing email connections,
accepting messages, and relaying them to the appropriate systems. The appliance can service email
connections from the Internet to recipients hosts inside your network, and from systems inside your
network to the Internet. Typically, email connection requests use Simple Mail Transfer Protocol (SMTP).
The appliance services SMTP connections by default, and acts as the SMTP gateway, also known as a
mail exchanger or “MX,” for the network.
accepting messages, and relaying them to the appropriate systems. The appliance can service email
connections from the Internet to recipients hosts inside your network, and from systems inside your
network to the Internet. Typically, email connection requests use Simple Mail Transfer Protocol (SMTP).
The appliance services SMTP connections by default, and acts as the SMTP gateway, also known as a
mail exchanger or “MX,” for the network.
The appliance uses listeners to service incoming SMTP connection requests, A listener describes an
email processing service that is configured on a particular IP interface. Listeners apply to email entering
the appliance, from either the Internet or from systems within your network trying to reach the Internet.
Use listeners to specify criteria that messages and connections must meet in order to be accepted and for
messages to be relayed to recipient hosts. You can think of a listener as an “SMTP daemon” running on
a specific port for each IP address specified. Also, listeners define how the appliance communicates with
systems that try to send email to the appliance.
email processing service that is configured on a particular IP interface. Listeners apply to email entering
the appliance, from either the Internet or from systems within your network trying to reach the Internet.
Use listeners to specify criteria that messages and connections must meet in order to be accepted and for
messages to be relayed to recipient hosts. You can think of a listener as an “SMTP daemon” running on
a specific port for each IP address specified. Also, listeners define how the appliance communicates with
systems that try to send email to the appliance.
You can create the following types of listeners:
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Public. Listens for and accepts email messages coming in from the Internet. Public listeners receive
connections from many hosts and direct messages to a limited number of recipients.
connections from many hosts and direct messages to a limited number of recipients.
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Private. Listens for and accepts email messages coming from systems within the network, typically
from internal groupware and email servers (POP/IMAP), intended for recipients outside the network
in the Internet. Private listeners receive connections from a limited (known) number of hosts and
direct messages to many recipients.
from internal groupware and email servers (POP/IMAP), intended for recipients outside the network
in the Internet. Private listeners receive connections from a limited (known) number of hosts and
direct messages to many recipients.
When you create a listener, you also must specify the following information:
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Listener properties. Define global properties that apply to all listeners, and properties specific to
each listener. For example, you can specify the IP interface and port to use for a listener, and whether
it is a public or private listener. For details on how to do this, see
each listener. For example, you can specify the IP interface and port to use for a listener, and whether
it is a public or private listener. For details on how to do this, see
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