Network Router Guide

Network Router Guide

Network Router Functions:

This network router guide describes some of the many functions of your router:

  • It serves as the local “node” for the Wide Area Network (WAN), which is generally understood as the Internet or “cloud.” To do this, it connects directly to your broadband modem (usually a cable modem but it could also be a DSL modem or satellite modem, depending upon what Internet Service Provider (ISP) you have contracted with.
  • It creates a Local Area Network (LAN) with all the devices connected to it.
  • It provides Wifi access (In which case it is called an “Access Point” or AP) to tablets & computers in the home, allowing them to operate as if physically connected to the router.
  • It serves as a “network splitter” to share the Internet connection to all the connected devices (printers, consoles, etc) on the local network. Depending upon the router, as many as five devices may be able to attach via Cat5 cable, and many more devices (often up to 50) may connect via WiFi. When connected to the router all the devices may share the Internet access and share data with the other devices on the network.
  • It has a “firewall” that protects your home network from outside intruders/hackers.
  • It offers a means to selectively allow/deny connections between devices on either side of the router.
Wireless Router Layout

Image courtesy of about.com

One function that allows a networked device to be accessed from outside of your network is called “Port Forwarding.” A second function that you can use to provide remote access to your security camera(s) is called the “De-Militarized Zone” (DMZ). Either method is relatively simple to set up. I will provide guides to these in later articles. This network router guide is meant to help you understand the general purpose and functions of the router.

Network Router Concepts:

The network router configuration depends upon a few basic concepts. They include IP address, Registered IP, Dynamic IP, Static IP, Firewall, NAT function, Private IP, MAC address, Ports, and DMZ. Unfortunately, those concepts are not well understood by ordinary users. Let me explain a bit more about each:

  1. IP address. It is shorthand for Internet Protocol (IP) address. Every device on every network must have an address in order to communicate to any other device. Each IP address consists of four numbers separated by three periods (called “dot”). Each number can take a value from 0 to 255. So, an example of an IP address might be something like 23.45.67.89 which would be read as “twenty-three dot fourty-five dot sixty-seven dot eighty-nine.”
  2. Registered IP. Most IP addresses are registered and are exclusive across the world. In other words, if you have been assigned the IP address of 23.45.67.89, then no one else on earth should have that same address. These address are typically assigned to us by our Internet Service Provider (ISP).
  3. Dynamic IP. IP addresses are provided temporarily (called a dynamic IP address) and will likely change when re-connecting after a disconnect between the router and the ISP.
  4. Static IP. Static IPs are usually assigned only by paying an extra fee to the ISP.
  5. Firewall. Your router filters the information that computers, which are outside of your network, can access on the inside of your network. It builds a virtual wall between the computers inside and those outside of your network. Like the metal panel separating the driver from the engine compartment of a vehicle, this is called a firewall.
  6. NAT function. Because there are a finate number of IPs available, and because there are an almost unlimited number of devices, there are not enough numbers to go around. The fix for this is to change the numbering scheme (currently called IPv4 and will be changed to IPv6)- but that will be a while in the making. So, home routers are designed with a function called Network Address Translation (NAT) that provides “Private IP addresses” that are unique ONLY within the local network. The effect of this function is that every device on a local network can use the same registered IP address and the router will sort the packets of data going both ways to assure that each local device communicates properly. It is similar to each home having the same postal address but someone within the home will sort the mail for each occupant. (A more complete description of this function is available here.)
  7. Private IP address. The home router assigns private (exclusive only on the local network) addresses to each device connected to the network. These numbers are generally in the range of 192.168.xxx.xxx.
  8. MAC address. This is a generally a physical address that is assigned to each device that will be attached to a network. It is normally assigned by the manufacturer and cannot be (easily) changed. However, some MAC addresses may be assigned locally or even spoofed (to imitate another device). IP addresses are assigned to a device associated with a particular MAC address. One does not need an extensive understanding of MAC addressing but it is often necessary to enter the MAC address of a device into the local router to have the router associate that device with a particular local IP address. The MAC address consists of six groups of two hexadecimal digits (the numbers 0-9 plus the letters a-f), separated by colons (:) or hyphens (-). (More information about MAC addressing can be found here.)
  9. Port number. Port numbers are used to further separate the functions available on the Internet. Registered ports are assigned by convention to certain functions. The most common port number is 80 which is used by your browser to communicate with a remote website via HTTP (Hyper-Text Transfer Protocol). Other common ports are usually numbered 1080 or less. Ports above that are generally called dynamic or private. (For a list of the most common registered ports see this article.)
  10. De-Militarized Zone (DMZ). The DMZ is a simple way to allow limited access to a server (web-server, FTP server, game server, etc) from outside your network and still retain a security firewall for all other devices on your network.

Network Router Configuration:

Log in to your router’s configuration page. The default URL is often 192.168.0.1 or 192.168.1.1 (or similar). The username is often ADMIN but it may change according to the brand of the router. Some routers default to no password while others may use PASSWORD as the password. Consult your router’s “Quick Start” document for the proper log in URL and credentials. If you do not have the original documents, visit the manufacturer’s website to download electronic copies. Alternately, just “Google” the brand (and optionally the model number) and “configuration page.”

If your router has previously been configured and you do not have the credentials to change it, you can always reset the device. Usually, there is a small hole in the router’s cover that allows access to an internal monetary switch. Press a pen or paper clip in the hole to contact the switch while you power on the router. Continue holding the switch until the lights on the router all blink a couple times and then stabilize. At that point, the device should be reset to its default / factory settings and you can use the default credentials to set it up.

Most newer routers have a configuration “wizard” or some sort of automated configuration. At a minimum, you should assure that the device is set to use the WPA/WPA2 security for WiFi. Then set a password for WiFi access and another password for the system configuration.

Advanced Router Configuration is required to view your security camera(s) from outside your network. We will have a guide for that in a later article.

See the links in the “Networking” box below to visit the other articles in this series.
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