Network Management Gateway

As we all know, walking from one room to another must go through one door. Similarly, sending information from one network to another must go through a "Gateway", which is the gateway.

What is gateway
A gateway is a gateway that connects a network to another network ".

There are also many types of gateways according to different classification standards. The Gateway in TCP/IP protocol is the most commonly used. The "Gateway" mentioned here refer to the gateway under TCP/IP protocol.

So what is the gateway? A gateway is essentially an IP address from a network to another network. For example, if Network A and Network B exist, the IP address range of Network A is "192.168.1.1 ~ 192. 168.1.254 ", The subnet mask is 255.255.255.0, And the IP address range of Network B is" 192.168.2.1 ~ 192.168.2.254 ", and the subnet mask is 255.255.255.0. Without a router, the two networks cannot communicate with each other through TCP/IP, even if the two networks are connected to the same vswitch (or hub, the TCP/IP protocol also determines that the hosts in the two networks are in different networks based on the subnet mask (255.255.255.0. To realize the communication between the two networks, you must use the gateway. If the host in Network A finds that the destination host of the data packet is not in the local network, it forwards the data packet to its own gateway, and then the gateway forwards the data packet to the gateway of Network B, the gateway of Network B is then forwarded to a host of Network B. The same is true for packet forwarding from Network B to Network.
Therefore, only the IP address of the gateway can communicate with each other through the TCP/IP protocol. Which machine is the IP address? The IP address of a gateway is the IP address of a device with the routing function. A device with the routing function has a router and a server with the routing protocol enabled (essentially equivalent to a router), proxy server (also equivalent to a vro ).

What is the default gateway?

If you find out what the gateway is, the default gateway is easy to understand. Just like a room can have multiple doors, a host can have multiple gateways. The default gateway means that if a host cannot find an available gateway, it sends data packets to the default gateway, which processes data packets. The gateway currently used by the host generally refers to the default gateway.

How to set the Default Gateway

The default gateway of a computer cannot be specified at will, and must be correctly specified. Otherwise, a computer will send data packets to a computer that is not the gateway, and thus cannot communicate with other networks. The default gateway can be set manually or automatically.

1. manually set

Manual settings are applicable when the number of computers is small and the TCP/IP parameters remain unchanged. For example, there are only a few to a dozen computers. This method requires setting the "Default Gateway" on each computer connected to the network, which is very difficult. Once the IP address of the default gateway must be modified due to migration or other reasons, this will cause a lot of trouble to the network management, so it is not recommended.

In Windows 9x, you can set the Default Gateway by right-clicking "Network neighbors" and clicking "properties" in the pop-up menu ", in the network Properties dialog box, select "TCP/IP protocol" and click "properties". On the "Default Gateway" tab, enter the IP address of the new default gateway.

Note that the default gateway must be an IP address in the CIDR block where the computer is located, rather than an IP address in another CIDR block.

2. Automatic settings

Automatic configuration is to use the DHCP server to automatically assign IP addresses, subnet masks, and default gateways to computers on the network. The advantage of this is that once the default gateway of the network changes, you only need to change the settings of the default gateway in the DHCP server, then all the computers on the network obtain the IP address of the new default gateway. This method is applicable to networks with large network sizes and variable TCP/IP parameters.

Another way to automatically obtain the gateway is to install the agent server software (such as MS proxy) client.ProgramThe method and method are similar to those of DHCP.

Article entry: dnbm responsible editor: dnbm