For IP communication subnets, how hosts within different subnets are addressed

The two hosts are A and B respectively, if host A uses the name to access host B, it must first use DNS to resolve the name of B to IP, and then host A uses its own IP as the source address, and B's IP encapsulates IP packets with the target address, and at the same time uses the subnet mask of A's own network card interface and B's IP to perform operations with it, if B and himself are on the same network airborne interface directly send out. However, the interface also needs to encapsulate IP packets into data frames when sending, which requires the MAC addresses of both hosts. If A knows B's MAC, it directly uses B's MAC as the destination address in the data frame, and if not, sends an ARP broadcast to the network to resolve B's IP to MAC.

After obtaining the MAC address of B, the data frame is encapsulated, and the data frame can be sent to the physical circuit with different level values. This is a one-way communication process from A to B in the same subnet.

During the communication process between different subnets, the DNS name resolution is the same. The source IP encapsulated in the packet is A, the destination IP is B, and the same is true for this. However, when host A uses the interface mask and B's IP to perform the calculation, it will find that the two IPs are not in the same subnet, which means that A will send this packet to the gateway of the network (usually the router of the network), and the gateway will do it.

In addition, when encapsulating the data frame, the host needs to know the MAC address of B, and broadcast it to the outside to require the MAC of B to be parsed, but B is not in the network, so only the ARP** function of the gateway can be realized, but the host A gets not the MAC address of B, but the MAC address of the gateway, so A encapsulates the destination address in the data frame as the local gateway. Next, when the data reaches the gateway, the gateway will read the destination IP in the packet, and perform ** according to the destination IP, when the destination IP in the packet remains unchanged, but the source MAC address and destination MAC address in the data frame will change. The source MAC address becomes the MAC address of the sending interface of the gateway, and the destination address may be the MAC address of host B or the interface MAC of the next router.

This is the process of one-way communication between different subnets. The communication from B to A is the same as this process.

1. The original host first determines that the destination host is not in the same subnet as itself according to the subnet mask, 2. The original host broadcasts ARP and interprets the MAC address of the default gateway, 3. Assembles the IP into the data link frame and broadcasts it to the default gateway, 4. After the default gateway takes out the IP address, it determines the route of the IP packet, 5. After receiving the packet, the NMS of the network management performs ARP to determine the physical address of the destination host, 6. The NMS of the destination host sends the frame to the destination host.

The network IDs can be derived by matching the IP addresses of the two hosts with their subnet masks.

For example: ip:

Subnet mask: Two addresses "AND", which gives the network ID of the network segment. In other words, IP addresses in this range can communicate with each other. All in the same network segment.

Then with and after the derivation of a reason:

After converting binary, it is: 1 and any number are still the value of that number. And 0 and any number sum are 0. So, after and after, it will be derived.

The result of the sum is the subnet network number.

Yes, the result is the network identity.

Query method:

1 The first step is to press the win r on the keyboard to open the operation, as shown in the figure below:

2 After the second step is opened and run, enter "cmd" in the input box and click "ok" as shown in the figure below

3 Click OK in the third step and enter the command prompt as the administrator as shown in the figure below

4 Enter "ipconfig all" in the command prompt and press enter as shown in the following image:

I also encountered this problem two days ago, and I was puzzled???

The IP address of each host of Xiaoyuan located in the same subnet satisfies the requirements of Li Hall ().

a.The network part is the same as the host part.

b.The network part is the same as the subnet part.

c.The subnet portion is the same as the host section.

d.Just the network part is the same.

Correct answer: The network part is the same as the subnet part.

What kind of network equipment do two hosts with the same IP address segment need to use to communicateHello dear, first of all, under the same network segment, there is no need for a gateway, and you can connect directly. A gateway is a device that connects two different networks. If the computer needs to connect to other network segments, it needs to send the data to the gateway for processing.

You can refer to the following configuration: the router is an ordinary home router, and the subnet mask below is router, RA computer P1, router, RB computer, P2, hereinafter referred to as A B 1, 2 connection: RA WAN port, RA WAN port, P1 network card, RB LAN port connection, P2 network card, assuming that the router does not have the dynamic routing function enabled. It is not configured, so A1 communicates with B2, but AB does not. Here is the IP address of the LAN port of the router, and the WAN port is not configured with an IP address, so the WAN port is not connected.

In this case, you need to configure the address for the WAN port separately. For example, after the A B configuration is complete, AB communicates with each other. At this time, A1, AB, and B2 are all passed, and 1b should also be passed, but 12 is not.

Because Route A does not know the situation of Route B's LAN port. Route A adds the routing table to the address that is sent to Route B. At this point, the road 1 to 2 is open.

b route adds a routing table so that 1 and 2 can communicate with each other. Of course, there are many other ways to connect and configure. It is not necessary that two WAN ports are interconnected, and LAN ports can be interconnected, but it is more troublesome.