Does the port on the switch have a MAC address?

MAC address refers to the address of the bridging router and the address of all devices that use your router to access the Internet, such as: computer, smart TV, mobile phone, tablet. The switch is just an adapter tap, no MAC address.

Information security managers hope that in the event of a security incident, not only can locate the computer, but also locate the actual location of the user, using the MAC and IP binding is a common way, IP address is the "name" of the computer, and this name is used when connecting to the network; The MAC address is the "ID number" of the computer network card, which will not be the same, because its number is determined when the manufacturer produces it. The modification of the IP address is convenient, and there are many tools and software that can easily modify the MAC address, and it is relatively easy to "impersonate the identity", and the network is not secure.

Following the idea of the "vase model" trust system, most people use protocol-based identity authentication technology (which can also be based on application identity authentication or CISCO's EOU technology), the purpose is to realize the binding of users, IPs, and MACs, from computer confirmation to human confirmation.

The identity authentication mode is through the security client software in the computer, to complete the identity authentication process of logging in to the network, and the MAC address is also sent to the authentication server through the client software.

Yes, each port of the switch has its own MAC address.

The transmission of network data is carried out on the basis of IP address, which is equivalent to the house number, otherwise the sender and receiver cannot be found.

However, the switch is based on MAC switching, which is equivalent to a personal ID card, and the MAC address of each NIC is unique.

The MAC address of the port is the hardware identifier, while the IP address is the software identifier. However, by default, the internal ports of the switch are all exchanged in MAC mode, so that the transmission is fast and does not need to be translated, and there is no need to configure an IP address (unless necessary).

Cisco's switches have their own MAC address for each port, because Cisco's switches have a ** chip for each port, but the domestic Huawei and H3C switches have a MAC address for each switch, because the domestic ** chip is one for each switch.

The third line is Mac

I don't know what information you're looking for, but you probably misunderstood.

It must be a MAC per port, because in Layer 2 operations, all MAC addresses are relied upon. Without a Mac, there's no way to mark the location of this port.

In addition to these MACs, the switch will also have some reserved MAC addresses that will be assigned to them by the CPU when you set up some virtual interfaces. So it's safe to assume that a Mac is needed for every logical port, even if it doesn't exist physically. The physical ports must be assigned these addresses at the time of production.

Ports without MAC are not able to communicate at the data link layer, and each port must have MAC.

It's the MAC address.

Summary. Not all switches use IP addresses for switching. Layer 2 switches use MAC addresses to lookup.

When a Layer 2 switch receives different packets from different ports, it can read the corresponding MAC address information from these packets. In this way, the Layer 2 switch can know which port the MAC address is connected to. Second, at this time, the Layer 2 switch will read the destination MAC addresses in the packet, and then find the relevant ports about these MAC addresses in these address information tables.

Not all switches use IP addresses for switching. The second-layer cross-belt smart circle replacement machine uses MAC address to find. When a Layer 2 switch receives different stupid packets from different ports, it can read the corresponding MAC address information from these packets.

In this way, the Layer 2 switch can know which port the MAC address is connected to. 2. At this time, the Layer 2 switching wide guess machine will read the destination MAC addresses in the packet, so as to find the relevant ports about these MAC addresses in these address information tables.

Can you add, I don't quite understand it.

No, because the switch is based on the MAC address table, if a port is tied to two MAC packets, it will not be sent normally! If you want to connect two computers to one port, you don't have to set it up! Directly connect a switch under a port, and connect to a computer on the back exchange!

Summary. MAC address table Generally speaking, there is a MAC address table for switches, which records the mapping relationship between each port of the switch and the MAC address of the terminal device, and the working principle of the switch is to select the destination port according to the mapping relationship between the port and the host address in the MAC table, and carry out Layer 2 data**. Therefore, through the MAC address table, you can find out which port connected to the terminal device corresponds to which host, and the mutual check between the MAC address and the port is carried out with the help of the MAC address table.

MAC address ruler royal table in layman's terms, not too much switch has a MAC address table, which records the mapping relationship between each port of the switch and the MAC address of the terminal device, and the working principle of the switch is to select the destination port according to the mapping relationship between the blind register port in the MAC table and the host ground grinding macro address, and carry out Layer 2 data**. Therefore, through the MAC address table, you can find out which port connected to the terminal device corresponds to which host, and the mutual check between the MAC address and the port is carried out with the help of the MAC address table.

Extended information: Software (Chinese mainland and Hong Kong language, called software in Taiwan) is a collection of computer data and instructions organized in a specific sequential order.

Generally speaking, software is divided into system software, application software, and middleware in between. Software does not only include computer programs that can be run on a computer (in this case, a computer in a broad sense), but also documents related to these computer programs are generally considered to be part of the software. To put it simply, software is a collection of programs and documents.

In addition, it also refers to the management system, ideological ideology, ideological and political consciousness, laws and regulations in the social structure.

1.The MAC address of the Layer 2 switch itself is optional. Layer 2 switches can be divided into:"Can be managed on the network"with"Not manageable"Two types, for"Can be managed on the network"of switches, we can configure its parameters; While"Not manageable"switches, it cannot be configured.

Because the Layer 2 switch is only used for data frames, and does not unpack the frames, its own MAC address is useless for data. However, sometimes we need to manage the configuration of the switch, which means that we need to communicate with the switch, and it needs a MAC address, which is equivalent to a host function for normal communication.

2.If a Layer 2 switch has a MAC address, it may not only have a single MAC, but multiple MACs, such as Cisco switches.

3.For Layer 2 switches, in our technical terminology, the built-in MAC address is called the static MAC address, and the MAC in the MAC table it learns is called:

dynamic mac address.

4.Finally, I would like to say that for a Layer 3 switch, it not only has a MAC address, but also every port has a MAC address, mainly due to the routing function.

The speed of the switch is really fast, much faster than the router, and much cheaper. However, it is a storm on the broadcast. Heterogeneous network interconnection. Security control cannot be effectively solved.

Switches can make use of VLANs (Virtual Local Area Networks) to solve some problems.

VLAN benefits include: <1> control broadcast storms.

2> Increase security.

3. Centralized management and control >.

The advantages of routing are: <1> network segment miniaturization.

2> Network congestion must be controlled.

3> Network security control.

4> Realize the interconnection between VLANs (virtual local area networks).

The switch doesn't have a MAC address! You can do it with one of your own computers, which means that the computer has to be dual-network.

I'm having the same issue and it hasn't been resolved yet. The solution that comes to mind is to manually add mac address-table on the Layer 3 switch. Looking forward to a better solution.

1. The router has two MAC addresses, one for WAN port and one for LAN port.

2. The switch does not have a MAC address, it is only responsible for bridging.

Home routers are mainly used for broadband sharing, that is, one broadband is provided to multiple networked devices to access the Internet at the same time.

There are two routers, one on the external network and one on the internal network, and the switch does not have a MAC address.

Need. The number of MAC addresses you supported, if you guessed correctly, should be the number of supported MAC address tables, right?

The principle of the switch is that when a port receives a packet, it will first broadcast to all other ports, and after broadcasting, the switch will correspond the source MAC address of the packet to this port and record it, and save it in the MAC address table, that is, record the host or terminal corresponding to the MAC address from this port in the MAC address table, and next time there is a packet sent from other ports to find this MAC address. The switch will check the MAC address table and find that the MAC corresponds to this port, and will send the packet directly to this port instead of sending broadcast packets.

That's what the MAC address table does. The size of the MAC address table of a switch is an important indicator to evaluate the grade of a switch, which determines how many hosts or terminals can be carried under the switch. This host or terminal not only refers to the host that can be accommodated by the switch port, but also the host that can be accessed after the switch is cascaded down several levels, and the number of hosts that can be accessed by the cascaded switch is magnified many times.

If the MAC address table is full in actual work, then there will be many packets that cannot find the corresponding port in the MAC table, then the packet will be broadcast in the switch, which is very easy to produce broadcast storms, and the LAN is the most afraid of broadcast storms.

Generally, the MAC address table of high-end switches is greater than 128K, and low-end switches also support about 1K. This indicator is not the same for various brands of switches, of course, the bigger the better. But the larger this metric, the more expensive the switch is.

So, it still depends on the number of hosts in your network.

Generally don't test the filter, see what you mean, you prepare a port to connect a lot of clients? That's not easy to control the traffic!

Different types of switches can support different MACs per port. On each port of the switch, there needs to be enough cache to remember these MAC addresses, and the average switch can usually store 1024 MACs, so if the network size is not very large, this parameter does not need to be considered too much. Of course, the more high-end the switch, the more MAC addresses can remember, depending on the size of the network to which it is connected.

Absolutely!

However, in general, this is not a major problem.

The MAC table is built by learning the source MAC of the frame.

A--- switch --- B

At the beginning, the MAC table of the switch is empty.

At this time, if A pings B, it is a simulation of AB communication.

A sends a broadcast packet to its own MAC.

After receiving this frame, the left interface of the switch will record the correspondence between the A-MAC --- the left interface.

Then the packet is sent out from the right interface.

After B receives, it finds that it is a request for its own MAC, it should respond, it also needs to construct a packet, the source MAC is its own MAC, the target MAC is A's MAC, but before it sends the packet out, the MAC layer protocol control circuit of the network card will first make a judgment, if the destination MAC is the same as the MAC of the current network card, then check the conflict, and this message will not be sent.

Therefore, B's packets will not be sent, A will not receive a response from B, and B's MAC cannot be obtained, so they cannot communicate.

In the end, there is only one MAC entry on the switch.

If the MAC address is different, the B packet can be sent normally, and the switch can record the correspondence between the B-MAC --- the right interface. AB can communicate normally.

Hope it helps!