Default Gateway

For a TCP / IP protocol configuration, is a direct arrival of the IP router's IP address. Default gateway can be configured in the IP routing table to create a default path.
IP address of the router to give the name of the local network and connect the machines must be out of traffic to this address in order to pass beyond the local network, so that the address be outside the local subnet IP address of the "gateways." Also Recently, the gateway is used when the host or network routing table heading input does not exist in the local routing table when they host the packet is sent to there.
Gateway (Gateway) is a network connection to another network's "gateway."
In accordance with different standards, there are many gateways. TCP / IP protocol, the gateway is the most commonly used, here we are
Said the "gateway" refer to TCP / IP protocol under the Gateway.
Gateway then in the end what is it? Gateway is essentially a network to other network IP address. A network such as network and B, Network A range of IP addresses "192.168.1.1 ~ 192. 168.1.254", for the subnet mask 255.255.255.0; Network B of the IP address of the range "192.168.2.1 ~ 192.168. 2.254 ", as a subnet mask of 255.255.255.0. In the absence of routers, the two networks can not be carried out between the TCP / IP communications, even if the two network connections on the same switch (or hub) on, TCP / IP protocol will be based on subnet Mask (255.255.255.0) to determine the two networks in a host of different network. In order to achieve these two communications networks, through Gateway. A network if the host was found in the packet is not the purpose of hosting the local network, put forward the packet to its own gateway, and then forwarded by the gateway to the network gateway B, B network gateway and then sent to the network B of a host (such as shown in the attached map). Network B to A network packet forwarding process. Therefore, only set up the gateway IP address, TCP / IP protocol can be achieved between the different networks to communicate with each other. Then the IP address of the machine, which is the IP address? Gateway is the IP address of the routing of the IP address of the device, with the routing equipment router, routing protocol enabled server (essentially the equivalent of a router), the proxy server (also The equivalent of a router).
What is the default gateway
If you understand what is the gateway, the default gateway is also a good understanding. Just like that there will be a room door,
A host to a number of gateways. The default gateway is the meaning of a host can not be used if the gateway, put the packet sent to default gateway specified by the gateway to deal with the packet. Gateway is now used by the host, in general refers to the default gateway.
How to set the default gateway
A computer's default gateway is not designated by the casual, must be properly designated, or a computer will
Gateway is not a packet sent to the computer, which can not compete with other computer communications network. Gateway's default settings are automatic and manual settings set in two ways.
1. Settings manually
Manual settings apply to the relatively small number of computers, TCP / IP parameters remain basically unchanged, for example, only a few dozen to Taiwan
Computer. Because this would require each of the networks linked to a computer set up on the "default gateway" very hard, because once the migration and other factors led to the need to modify the default gateway IP address to the network will bring big trouble So is not recommended to use.
In Windows 9x, set the default gateway is in the "Network Places" on the right-click in the pop-up menu, click
"Properties" on the network Properties dialog box, select the "TCP / IP protocol," click on "Properties" and "default gateway" to fill in a new tab in the default gateway IP address it.
Need to pay special attention to is this: By default gateway must be a computer's own network segment of IP addresses, and can not fill in the other
Segment of IP addresses.
2. Automatically set
Is automatically set to use DHCP server automatically to the computer network, the distribution of IP address, subnet mask and default gateway
. The benefit is that once the network's default gateway has changed, as long as a DHCP server to change the default setting of the gateway, then all the computer networks are a new default gateway IP address. This method is suitable for large-scale network, TCP / IP parameters may change in the network.
Another automatic access to the gateway through a proxy server to install software (such as MS Proxy) of client
To automatic, its principles and methods are similar and DHCP. Due to limited space, no longer on the details.
If you look at the beginning of routing knowledge, they would easily understand,
Into the command-line mode:
C: \> route print
There will be a route:
0.0.0.0 0.0.0.0 default IP Gateway Interface (machine IP) hop
For example, my machine:
0.0.0.0 0.0.0.0 192.168.100.254 192.168.100.233 1
Means: the needs of all packets transmitted, are the default gateway IP (Interface) sent out, of course, is to return from there after