Manual
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341 
ARP list entries of the switch, causing successful DOS attacks. 
 To summer up, it is very meaningful to develop the number limitation function of MAC and IP 
in port, VLAN. Switch can control the number of MAC address of ports and the number ARP, 
ND list entry of ports and VLAN through configuration commands. 
Limiting the number of dynamic MACand IP of ports: 
1.  Limiting the number of dynamic MAC. If the number of dynamically learnt MAC address by 
the switch is already larger than or equal with the max number of dynamic MAC address, 
then shutdown the  MAC  study function on this  port, otherwise, the port  can continue its 
study. 
2.  Limiting the number of dynamic IP. If the number of dynamically learnt ARP and ND by the 
switch is already larger than or equal with the max number of dynamic ARP and ND, then 
shutdown the ARP and ND study function of this port, otherwise, the port can continue its 
study. 
Limiting the number of MAC, ARP and ND of interfaces: 
1.  Limiting the number of dynamic MAC. If the number of dynamically learnt MAC address by 
the VLAN of the switch is already larger than or equal with the max number of dynamic 
MAC address, then  shutdown the  MAC study function  of all the ports in  this VLAN, 
otherwise, all the ports in this VLAN can continue their study (except special ports). 
2.  Limiting the number of dynamic IP. If the number of dynamically learnt ARP and ND by the 
switch is already larger than or equal with the max number of dynamic ARP and ND, then 
the VLAN will not study any new ARP or ND, otherwise, the study can be continued. 
41.2 The Number Limitation Function of MAC and IP in Port, VLAN 
Configuration Task Sequence 
1.  Enable the number limitation function of MAC and IP on ports 
2.  Enable the number limitation function of MAC and IP in VLAN 
3.  Configure the timeout value of querying dynamic MAC 
4.  Configure the violation mode of ports 
5.  Display and debug the relative information of number limitation of MAC and IP on ports  
1.  Enable the number limitation function of MAC and IP on ports 
Command 
Explanation 
Port configuration mode 
switchport mac-address dynamic maximum 
<value> 
no switchport mac-address dynamic 
maximum 
Enable and disable the number limitation 
function of MAC on the ports. 










