114074 LG 1.45 NETWORK CONFIGURATIONS AND INSTALLATION ISSUES

Network configuration is the process of setting a network’s controls, flow and operation to support the network communication of an organization and/or network owner. This broad term incorporates multiple configuration and setup processes on network hardware, software and other supporting devices and components.

In a networked environment, such as a company, typically there are many computers connected together using a router or a switch (for more information, see router or switch in the definitions section). In larger companies, there may be several different routers distributed in buildings and plant locations. A router allows any LAN-side computer communicate with computers and devices outside the LAN (local area network). Routers send data packets from one place to another place on a network. Routers use network addresses to route packets to the correct destination. For example, in a TCP/IP network, the IP (internet protocol) address of the network interface is used to direct router destinations. Because routers help computers inside the LAN “talk” with computers outside of the LAN. The security of a company’s LAN may be compromised by gaps of open ports in the router. Security measures may have been instituted to compensate for these vulnerabilities. Consult your network administrator to learn about the security measures taken to protect your network. VPN, or virtual private network, is one such security measure to protect the intelligence of the LAN. A computer outside the LAN must have an address or key known by the VPN to allow access to the LAN. Many companies use a VPN to connect two different LANs, thus allowing the transfer of data between the two networks.

Accessing the Wide Area Network (WAN) Figure shows LAN IP addresses using a common IP address, 10.2.100.x (192.168.x.x is another common address). Most devices are shipped with these addresses as its default. It is recommended to use these addresses for LANs.
Network Address Translation (NAT) Using the initial IP address, then converting it to a valid WAN IP address is how the network address translation works in theory. Once the IP address is changed, it is up to the network interface device (such as a router, gateway, switch, etc.) to keep track of which computers are talking on which ports. For example, if two local devices (PC1 and PC2 in Figure 3) both wanted to talk via port 1031, then the network interface device would have to change one of the port requests to the next available port, 1032.

Ports

In general, a network port is an endpoint to a logical connection. The port number identifies what type of port it is. For example, port 80 is used for HTTP traffic. When you type an address into the address bar of a web browser, your computer goes to find an IP address for the url you are requesting (http:// www.telex.com). To obtain this address, the computer contacts a DNS server (Domain Name Server). Once the IP address is found, it tries to connect to the http port of the network device (port 80). See Table 1 for a list of the more well-known Port numbers. Each network device can be set up to respond or not respond to the various ports. The function of responding or “hosting a service” is called “serving”.
If a second work station on the LAN wants to communicate to the same server, and happens to use the same source port number, then the LAN Modem will translate the source port number as well as the source IP address. In Table 2, a second LAN computer wants to access.
Amazingly, all the address translation that occurs takes place automatically in order to make web browsing and other functions easier. This is also a way for large web hosting services to speed up the network by having different devices perform different functions.
Ping a Computer

Pinging a computer on the network makes sure it is able to be “seen” and receive messages on the network. Note: You can also ping your RVON-8 card to verify that it is responding over the network by putting the cards IP address in place of the computer IP address. To ping a computer on the network, do the following,
1. From the Start Menu, open a Command Prompt screen.
3. . At the prompt, type the IP Address of the computer you wish to ping. (for example, 10.2.100.130) 3. Press Enter.
5. Note: If the computer you are pinging is not responding to the ping, you will receive a time out message in the command prompt screen.
  
  Possible Pitfall with Routers, Gateways, and Switches Anytime computers communicate through routers, gateways, and switches, they may be allowed or denied the connection. Network interface devices can be configured to block specific outgoing requests, as well as incoming requests, based on the IP address and/or port. This is one of the security mechanisms of a router. This also happens when broadcast messages are sent and received. To view the path an IP address takes to retrieve information, you can execute a tracert from the Command Prompt screen.
  
  To run tracert, do the following:
  1. From the Start Menu, open a Command Prompt screen.
  2. At the prompt, type tracert and type the url or IP address you want to trace.
  3. Press Enter