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A information backlink layer functions as a medium for conversation concerning two right linked hosts. At the sending entrance, it transforms the data stream into alerts bit by bit and transfers it to the hardware.  On the contrary, as a receiver, it receives info in the form of electrical indicators and transforms them into an identifiable body.

MAC can be categorised as a sublayer of the knowledge hyperlink layer that is accountable for bodily addressing. MAC address is a exceptional tackle for a network adapter allocated by the manufactures for transmitting knowledge to the spot host. If a gadget has quite a few network adapters i.e., Ethernet, Wi-Fi, Bluetooth, and many others., there would be diverse MAC addresses for each and every conventional.

In this article, you will understand how this sublayer will get manipulated to execute the MAC flooding assault and how we can avoid the attack from occurring.


MAC (Media Accessibility Manage) Flooding is a cyber-attack in which an attacker floods network switches with phony MAC addresses to compromise their security. A switch does not broadcast network packets to the whole community and maintains network integrity by segregating facts and producing use of VLANs (Digital Neighborhood Area Community).

The motive guiding MAC Flooding assault is to steal knowledge from a victim’s process that is being transferred into a network. It can be achieved by forcing the switch’s rightful MAC desk contents out, and the switch’s unicast actions. This effects in the transfer of sensitive information to other elements of the network and ultimately turning the change into a hub and producing significant portions of incoming frames to be flooded out on all ports. As a result, it is also referred to as the MAC deal with desk overflowing assault.

The attacker can also use an ARP spoofing attack as a shadow assault to let himself to carry on possessing accessibility to non-public data afterward the community switches retrieve by themselves from the early MAC flooding assault.


To promptly saturate the table, the attacker floods the swap with a massive quantity of requests, each individual with a fake MAC handle. When the MAC table reaches the allocated storage restrict, it commences taking away aged addresses with the new ones.

Just after getting rid of all the legitimate MAC addresses, the swap begins broadcasting all the packets to each and every swap port and will take on the position of network hub. Now, when two valid end users attempt to converse, their details is forwarded to all accessible ports, ensuing in a MAC table flooding attack.

All the authentic end users will now be equipped to make an entry until this is done. In these situations, destructive entities make them a component of a community and mail destructive knowledge packets to the user’s pc.

As a outcome, the attacker will be ready to capture all the ingoing and outgoing website traffic passing through the user’s process and can sniff the confidential facts it includes. The subsequent snapshot of the sniffing resource, Wireshark, shows how the MAC deal with table is flooded with bogus MAC addresses.

Attack Avoidance

We need to generally get precautions to protected our devices. Fortunately, we have instruments and capabilities to end thieves from getting into the technique and to answer to assaults that place our program at threat. Halting the MAC flooding attack can be carried out with port security.

We can achieve that by enabling this characteristic in port protection by utilizing the switchport port-security command.

Specify the greatest quantity of addresses that are permitted on the interface using the “switchport port-security maximum” benefit command as underneath:

switch port-safety utmost 5

By defining the MAC addresses of all known units:

switch port-protection optimum 2

By indicating what ought to be finished if any of the higher than conditions are violated. When a violation of switch Port Security happens, Cisco switches may be configured to reply in a single of 3 ways Protect, Limit, Shutdown.

The defend manner is the stability infringement mode with the minimum safety. Packets that have unknown resource addresses are dropped, if the range of secured MAC addresses exceeds the port’s limit. It can be averted if the amount of specified most addresses that can be saved in the port is enhanced or the range of secured MAC addresses is decreased.  In this situation, no evidence can be located of a info breach.

But in the restricted method, a details breach is documented, when a port stability violation takes place in the default protection violation manner, the interface is error-disabled and the port LED is killed. The breach counter is incremented.

The shutdown manner command can be made use of to get a secure port out of the mistake-disabled condition. It can be enabled by the command pointed out below:

swap port-safety violation shutdown

As properly as no shutdown interface setup manner instructions can be made use of for the same function. These modes can be enabled by the use of the commands offered below:

swap port-stability violation secure

swap port-security violation prohibit

These attacks can also be prevented by authenticating the MAC addresses versus the AAA server recognized as authentication, authorization, and accounting server. And by disabling the ports that aren’t used quite generally.


The outcomes of a MAC flooding attack can differ looking at how it is applied. It can final result in the leak of own and sensitive data of the person that could be applied for destructive functions, so its prevention is necessary. A MAC flooding assault can be prevented by a lot of procedures which includes the authentication of uncovered MAC addresses in opposition to “AAA” Server, and so on.

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