If an entry is incorrect, clear the ARP cache to resolve the problem.
HOW TO PREVENT MAC ADDRESS FLOODING MAC
Compare the output with the correct IPv4 address and MAC address combinations. View the ARP cache on the computer that is experiencing the problem. On large networks with low bandwidth, multiple ARP broadcasts could cause data communication delays.
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What is the typical goal of MAC spoofing?.What is the difference between Mac flooding and MAC spoofing?.What is the difference between ARP poisoning and MAC spoofing?.What are the two problems that can be caused by a large number of ARP request and reply messages?.
HOW TO PREVENT MAC ADDRESS FLOODING PC
I would rather solve the source of the problem, the fact that one of the distribution switches is not aware of, or forgets about the MAC address of the PC in the VTP domain. VTP pruning wouldn't solve it because the vlan that is involved in flooding streches past the LRE link. As soon as an ARP request has passed and the MAC address is known, unicast flooding stops. The only reason why my distribution switch is flooding is because there is no entry in the MAC database. Furthermore the VTP domains in my network are separated by a layer 3 core. And the switches involved can - by design - only be part of one VTP domain. the vlan interface) of my distribution switch, the different VTP domains cannot be part of the same broadcast domain. Since my L2 network terminates at a routing interface (ie. A broadcast domain can be within the same LAN segment or it can be bridged to other LAN segments. Thanks! Sorry but to my understanding a broadcast domain is a logical division of a computer network, in which all nodes can reach each other by broadcast at the data link layer. Has anyone seen this before? Could this have something to do with asymmetric routing paths from the distribution layer to and from the core?Īnd what can be done to stop it? Apart from making static arp entries in de distribution layer. The MAC address of the PC is only in one 3550 and traffic is flooded into the VTP domain again. In order to prevent this from happening again i also increased the MAC aging timer to 14400 seconds - making it equal to the ARP timeout value. Pinging the PC solved the problem - the MAC table got populated with the right MAC address and that stopped the flooding. I looked in the distribution layer and on one of the 3550's i missed the MAC entry for the user's PC in the VTP domain. Not very much but enough to kill the LRE line. While sniffing, it appeared to be caused by a stream of traffic from outside the VTP domain towards a machine within the VTP domain. Last week i found out that an LRE device - also in the access layer of this VTP domain - was suffering from traffic being flooded onto the access layer. One of em has several 2960 access layer switches in stacks, a distribution layer (2x 3550 with L2 interconnects and HSRP) to form the L2/元 boundary, and both have their own uplink to their own core switch (6500's - only 元).
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In our 3-layered cisco campus network we have several VTP domains.