Difference between revisions of "MAC address flooding"
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| + | = What is MAC address flooding = | ||
| + | MAC address flooding is an attack where the attacker sends lots of frames to the switch with random ''source MAC addresses'' and flooding the MAC-address table in the switch. The CAM - Content Addressable Memory - gets full, and frames from valid hosts are flooded out of all ports. | ||
| + | = Protecting against MAC Address flooding = | ||
| + | Is done on a port basis. | ||
| + | == Example == | ||
| + | Up to five MAC address are allowed on user ports. | ||
| + | === Port shutdown === | ||
| + | If you want the port to go in '''err-disabled''' if more than five MAC-addresses are seen on the port | ||
| + | <pre> | ||
| + | Switch(config)# interface fastethernet 0/1 - 24 | ||
| + | Switch(config-if)switchport port-security maximum 5 | ||
| + | Switch(config-if)switchport port-security violation shutdown | ||
| + | </pre> | ||
| + | === Allow legal traffic and discard rest. No logging === | ||
| + | If you want the port to go in '''err-disabled''' if more than five MAC-addresses are seen on the port | ||
| + | <pre> | ||
| + | Switch(config)# interface fastethernet 0/1 - 24 | ||
| + | Switch(config-if)switchport port-security maximum 5 | ||
| + | Switch(config-if)switchport port-security violation protect | ||
| + | </pre> | ||
| + | === Allow legal traffic and discard rest. SNMP trap logging === | ||
| + | If you want the port to go in '''err-disabled''' if more than five MAC-addresses are seen on the port | ||
| + | <pre> | ||
| + | Switch(config)# interface fastethernet 0/1 - 24 | ||
| + | Switch(config-if)switchport port-security maximum 5 | ||
| + | Switch(config-if)switchport port-security violation restrict | ||
| + | </pre> | ||
| + | |||
| + | |||
| + | </pre> | ||
| + | |||
| + | |||
[[Category:Cisco]][[Category:CCNA]][[Category:CCNP]][[Category:IOS]][[Category:Network]][[Category:CCNP3]] | [[Category:Cisco]][[Category:CCNA]][[Category:CCNP]][[Category:IOS]][[Category:Network]][[Category:CCNP3]] | ||
Revision as of 18:15, 7 May 2009
Contents
What is MAC address flooding
MAC address flooding is an attack where the attacker sends lots of frames to the switch with random source MAC addresses and flooding the MAC-address table in the switch. The CAM - Content Addressable Memory - gets full, and frames from valid hosts are flooded out of all ports.
Protecting against MAC Address flooding
Is done on a port basis.
Example
Up to five MAC address are allowed on user ports.
Port shutdown
If you want the port to go in err-disabled if more than five MAC-addresses are seen on the port
Switch(config)# interface fastethernet 0/1 - 24 Switch(config-if)switchport port-security maximum 5 Switch(config-if)switchport port-security violation shutdown
Allow legal traffic and discard rest. No logging
If you want the port to go in err-disabled if more than five MAC-addresses are seen on the port
Switch(config)# interface fastethernet 0/1 - 24 Switch(config-if)switchport port-security maximum 5 Switch(config-if)switchport port-security violation protect
Allow legal traffic and discard rest. SNMP trap logging
If you want the port to go in err-disabled if more than five MAC-addresses are seen on the port
Switch(config)# interface fastethernet 0/1 - 24 Switch(config-if)switchport port-security maximum 5 Switch(config-if)switchport port-security violation restrict
</pre>