The function of the Router is to act as a spokesperson for your network to the Internet. The Router takes any communications request from the “non-routable” or “private network” IP device on your network and passes it to the outside world with your single and unique WAN IP address assigned to your home or business Internet service.
IP devices on your network can be, but aren’t limited to, computers, notebooks, printers, scanners, tablets, telephones, Smart TVs, gaming systems, Smart Home and security devices.
If we program all of the devices on a LAN with non-routable IP addresses, we can have hundreds of devices in our home or business using addresses that other homes and businesses may be using, but with no conflict, because all of our devices look like a single device with a unique WAN IP address to the rest of the world.
The most popular non-routable IP ranges start with 192.168.x.y. Most out-of-the-box Routers will have a factory programmed IP address of 192.168.0.1 or 192.168.1.1 or 192.168.2.1.
For a device to see another device on your network, the first three fields, or octets, of the IP address have to be the same. This generally limits any network to using addresses for every device which start with the same first three octets and unique numbers for the fourth octet. These first three octets are referred to as your “network number” or “Subnet”. A typical home or office may have a network number or Subnet of 192.168.1.x and every device has only got a different and unique fourth octet. Which Subnet you choose makes absolutely no difference, as long as you are consistent throughout your network.
Keeping track of all of these numbers is a daunting task for anyone, so Routers have a function called DHCP built in by default. DHCP is a feature which gives out TCP/IP addresses to devices requesting them. The network device is usually set to “Dynamic” IP, which means it’s not configured for any particular address, but will ask the DHCP for a temporary address. When you connect a phone, for example, to your home WiFi, the DHCP will assign that phone a unique IP address within the LAN’s subnet. This is called an “address lease”.
If address leases were permanent, you would lose an address every time a guest visited and used your WiFi, so we make leases expire after a given time. This is a user-definable period in your Router setup. The temptation is to expire a lease after a day and therefore have plenty of IP addresses to go around (as you might configure if you’re the IT guy for coffee shop offering free WiFi), but the caution is that you may lose connection to a printer or scanner, for example, because it got a new IP address after being off for a few days. It’s always a good idea to set your DHCP Lease Time to a day longer than your longest potential vacation.
DHCP services have always got an address range setting for the available pool of IPs. This often looks like 192.168.1.100 – 192.168.1.200 as an example. The starting address is arbitrarily chosen within the 254 available addresses of your Subnet. If you have no devices that have a permanently assigned IP address, you could theoretically make this DHCP address range everything after your Router’s address, eg: 192.168.1.2 – 192.168.1.254.
In practice, keep parts of the Subnet available for permanent IP addresses. This is particularly useful for printers, scanners, media servers, network accessible storage devices (NAS) and security DVRs. Setting permanent IP addresses (and recording them properly to not run into conflicts!) will allow you to always connect with them, even after a power-off state longer than your address lease, where the device may get a different address. I like to set my DHCP range between 192.168.1.100 and 192.168.1.200, reserving addresses below the 100 octet for printers, scanners, NAS boxes, media servers, access points and my work PC (which I like to log in remotely to).
A common problem that often occurs is having more than one DHCP on a LAN. This will create conflicting addresses and periodic losses of connections. Routers, Firewalls and WiFi devices are usually configured with DCHP turned on at the factory. If you install such a device as a “Range Extender” or “Access Point” on your network and want to maintain all devices in a single Subnet, you MUST disable the DHCP function on the new device.
Configuring your WiFi is a simple matter of picking a wireless network name (SSID) and assigning it a security key or password. There are a number of different security settings, which, for the most part, are not important in the context of a home or small business. The WPA2 security setting, which is usually set as default, will satisfy almost all security requirements.
You will most likely see the WiFi settings in triplicate. One is for 5GHz, one is for 2.4GHz and one is for guests. Set up each SSID and password to enable each.
5GHz is a higher speed wireless frequency which is beneficial for close devices, like a TV or gaming system near the Router.
2.4GHz isn’t as fast as 5GHz but has better range. You may want to connect to this with a mobile phone, Smart Home device or an outside security camera, for example.
Both of these Wireless networks should be protected with excellent passwords because passersby can also see your network and gain access with an easy password guess. When you’re giving out WiFi access to casual visitors, the Guest WiFi would be the better option.
Guest WiFi has the additional level of protection of Firewalling the guest WiFi user from all other devices on the network. Your WiFi password doesn’t need to be as secure and you can rest easily knowing that the user can’t access any other devices on your network.
DNS server configuration is an important part of your internet functionality. Domain Name Servers (DNS) are the machines at your Internet Service Provider (ISP) which cross reference or “resolve” IP addresses to their URLs. Your Router may only pass along a request to 22.214.171.124, but your DNS servers know that you actually meant “Google.com”.
Your DNS servers are usually set automatically once your Router sees the internet, but in some cases, your ISP will provide you with these IP addresses for you to configure manually.