User's Manual

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Scenario:
Four PCs as shown in the above figure connect to port 1/0/5、1/0/7、1/0/9、1/0/11 of switch, all the four PCs
belong to the default VLAN1. As required by the network environment, dynamic learning is enabled. PC1
holds sensitive data and can not be accessed by any other PC that is in another physical segment; PC2 and
PC3 have static mapping set to port 7 and port 9, respectively.
The configuration steps are listed below:
1. Set the MAC address 00-01-11-11-11-11 of PC1 as a filter address.
Switch(config)#mac-address-table static 00-01-11-11-11-11 discard vlan 1.
2. Set the static mapping relationship for PC2 and PC3 to port 7 and port 9, respectively.
Switch(config)#mac-address-table static 00-01-22-22-22-22 interface ethernet 1/0/7 vlan 1
Switch(config)#mac-address-table static 00-01-33-33-33-33 interface ethernet 1/0/9 vlan 1
16.4 MAC Table Troubleshooting
Using the show mac-address-table command, a port is found to be failed to learn the MAC of a device
connected to it. Possible reasons:
 The connected cable is broken.
 Spanning Tree is enabled and the port is in “discarding” status; or the device is just connected to the
port and Spanning Tree is still under calculation, wait until the Spanning Tree calculation finishes, and
the port will learn the MAC address.
 If not the problems mentioned above , please check for the switch port and contact technical support
for solution.
16.5 MAC Address Function Extension
16.5.1 MAC Address Binding
16.5.1.1 Introduction to MAC Address Binding
Most switches support MAC address learning, each port can dynamically learn several MAC addresses, so
that forwarding data streams between known MAC addresses within the ports can be achieved. If a MAC
address is aged, the packet destined for that entry will be broadcasted. In other words, a MAC address
learned in a port will be used for forwarding in that port, if the connection is changed to another port, the
switch will learn the MAC address again to forward data in the new port.
However, in some cases, security or management policy may require MAC addresses to be bound with the
ports, only data stream from the binding MAC are allowed to be forwarded in the ports. That is to say, after a
MAC address is bound to a port, only the data stream destined for that MAC address can flow in from the
binding port, data stream destined for the other MAC addresses that not bound to the port will not be allowed
to pass through the port.