Use Windows NT Server as a Router

Up to now, TCP/IP has become the most widely used universal network protocol. It is recognized by many computer users. With TCP/IP, you can easily connect networks of different network types and operating systems, and connect them to the Internet.

In TCP/IP network interconnection, different networks often use routers. Traditional hardware-based routers are often expensive and not accepted by General units. In the network connection process, two or two local networks are interconnected, you do not need to use expensive dedicated routers. In fact, there are many network operating systems that provide routing functions, but they are only software-based routing, such as Windows NT Static Routing System, NOVELL multi-protocol routing, and other software-based routing technologies.

Software-based routing is definitely not as functional as a hardware-based dedicated router. But it already has the basic functions of the router. You can implement basic routing functions. Software-based routing is ideal for the interconnection between small networks. The following uses the interconnection between networks as an example to describe the software-based routing technology.

As we all know, in TCP/IP Protocol, IP Protocol Internet Protocol provides addressing and routing functions. When data is sent over the network, the data is first packaged into IP data packets. IP allows data packets to be transmitted from one place to another on the network. Data is transmitted over the network in one way. In one Ethernet, it is easy to send packets from one machine to another, because Ethernet is a broadcast-based network, messages sent from any machine will be immediately monitored by all machines on the Internet. Only those machines with the same address in the message will send a response. Other machines will ignore this message. It can be seen that in the same network, no route is required for each message to directly reach its destination. However, when two or more networks are interconnected, the situation is quite different. 1 shows that when a machine in the network Counter sends information to a machine in the network Computer Center, if there is no route from the network Counter to the network Computer Center, the information cannot be sent at all.

From the above analysis, we can know that the information in the same network can be smoothly transmitted, so if there is such a machine: a machine that belongs to both the network Counter and the network Computer Center. Through it, two different networks can transmit information to each other. When an NT router is created for each network, the creation process is as follows:

1. install two NICs on the same Windows NT machine. The NIC can use any Nic supported by NT. Windows NT can be either a Windows NT Server or a Windows NT Workstation, preferably version 3.51 or later. This article is based on Win? Chinese version of dowsNTServer4.0.

2. Go to the control panel and install the TCP/IP protocol.

3. Configure the NIC: Configure an IP address for each Nic. The two IP addresses belong to different IP addresses in the network.

4. Set the IP address routing function of Windows NT to Enable.

5. Confirm and restart the computer.

In this way, the NT router can work between the two networks. The NT router works as follows:

A Computer in the Counter network, Counter01, sends information to a Computer in the Computer Center network CC01. It queries whether CC01 is in the same network as itself. If it is in the same network, the information packet is transmitted from Counter1 to CC01, And the IP packet is transmitted in the same network. If you find that CC01 is not in the same network through the query, send the Counter1 point and find that you do not know how to reach CC01. In this case, the information is sent to the default gateway: When ROUTER1 is in the network, the default router of each machine in the network Counter must be set to ROUTER1 and the IP address is the IP address of router1. For each machine in the network, the default router is actually such a machine. If the destination address cannot be found at the information point, it sends the information to the default router, after receiving the information, ROUTER1 is checked by the IP software running on it. By checking the package content, you can determine the source address and target address in the IP package. If the source IP address in the IP package is in the same network as the IP address of the first Nic, the target IP address is in the same network as the second Nic, it sends the information through its second network card, so that the information is transmitted to the network Computer Center. Once the information package enters the Computer Center of the network, the target Computer in the network listens to the information package and sends it to itself, so it receives the information package and reassembles it.

The above is the situation where the NT router works in two networks. It is indeed competent for its tasks, but if there are three or more networks, the method mentioned above is not competent.

See the following network structure:

The ROUTER1 router can only transmit the message 192.168.101 to network 168.168, but cannot transmit the information from network 192.168.101 to network Admin195.125.96 ). However, it doesn't matter. The Route commands in NT can tell the router how to reach AdminCenter. For ROUTER1 and ROUTER2, they both belong to the Computer Center network. Therefore, the router must be able to use the ComputerCenter network 193.169.101) send to AdminCenter network 195.125.96), you only need to tell ROUNTER1 Network Computer Center ROUTER2 NIC address.

The command format is as follows:

C: ι Winnt Lambda routeadd195. 125.96168.168.100.100

This command will add route information to the ROUTER1 routing table, meaning: send any IP packet destined for 195.125.96.xxx to 168.168.100.100.

Similarly, for network AdminCenter, vrorourouter2 does not know how to reach Counter network 192.168.101.

The command format is as follows:

C: ι Winnt Lambda routeadd192. 168.101168.168.100.101

Same as above.

In fact, we can build a static route table to achieve the above functions. We can create a static route table on ROUTER1 and ROUTER2. A static route table requires a destination and a gateway, the target is the network ID or network name of the target network, and the gateway is the IP address or host name connected to the target network. The content is as follows:

For ROUTER1, use the network ID of the network Admin and the IP address of the default gateway to construct the route table. The gateway is the IP address or host name of the computer connected to the target network. The static route table is as follows:

Target Network Gateway

195.125.96168.168.100.100

AdminROUTER2

For ROUTER2, use the network ID of the network Counter and the IP address of the default gateway to construct the route table. The gateway is the IP address or host name of the computer connected to the target network.

The static route table is as follows:

Target Network Gateway

192.168.101168.168.100.101

CounterROUTER1

The content of the corresponding NETWORKS file is as follows:

# WindowsNT4.0NetworksContent
Counter192.168.101
Admin195.125.96
Loopback127
ComputerCenter168.168

The content of the corresponding HOSTS file is as follows:

192.168.101.1COUNTER1counter1.saturn.com
168.168.100.1CC01cc01.saturn.com
#......

So far, information can be transmitted between the three networks through routing.

Someone said that another vro can be configured between Counter and AdminCenter. Indeed, if you configure ROUTER3 between Counter and Admin, there will be one more path for each machine on the network, in this way, communication can still be performed between a path due to congestion or unexpected failure. This requires that each computer in the network be configured to use multiple gateways.