H3C Technologies H3C S12500-X Series Switches - Manual (Page 101)

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Configuring port security
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Overview
Port security combines and extends 802.1X and MAC authentication to provide MAC-based network
access control. It applies to networks that require different authentication methods for different users on
a port.
Port security prevents unauthorized access to a network by checking the source MAC address of inbound
traffic, and it prevents access to unauthorized devices or hosts by checking the destination MAC address
of outbound traffic.
Port security can control MAC address learning and authentication on a port to make sure the port learns
only source trusted MAC addresses.
A frame is illegal if its source MAC address cannot be learned in a port security mode or it is from a client
that has failed 802.1X or MAC authentication. The port security feature automatically takes a predefined
action on illegal frames. This automatic mechanism enhances network security, and reduces human
intervention.
NOTE:
For scenarios that require only 802.1X authentication or MAC authentication, H3C recommends you use
the 802.1X authentication or MAC authentication feature rather than port security. For more information
about 802.1X and MAC authentication, see "
791H
Configuring 802.1X " and "
792H
Configuring MAC
authentication ."
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Port security features
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NTK
The need to know (NTK) feature prevents traffic interception by checking the destination MAC address in
the outbound frames. The feature ensures that frames are sent only to hosts that have passed
authentication or whose MAC addresses have been learned or configured on the access device.
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Intrusion protection
The intrusion protection feature checks the source MAC address in inbound frames for illegal frames, and
takes a predefined action on each detected illegal frame. The action can be disabling the port
temporarily, disabling the port permanently, or blocking frames from the illegal MAC address for 3
minutes (not user configurable).
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Port security modes
Port security supports the following categories of security modes:
• MAC learning control—Includes two modes: autoLearn and secure. MAC address learning is
permitted on a port in autoLearn mode and disabled in secure mode.