Mismatched Wi-Fi Security SettingsSeemingly the most common cause of wireless network setup issues, incompatibility in settings between two Wi-Fi devices (such as the router and a PC) will prevent them from being able to make a network connection. Check the following settings on all Wi-Fi devices to ensure they are compatible:
- Network mode: A router must be enabled to support all versions of Wi-Fi used by the network clients. For example, routers configured to run in "802.11g only" mode will not support 802.11n or old 802.11b devices. To fix this kind of network failure, change the router to run in mixed mode.
- Security mode: Most Wi-Fi devices support multiple network security protocols (typically different variations of WPA and WEP). All Wi-Fi devices including routers belonging to the same local network must use the same security mode.
- Security key: Wi-Fi security keys are passphrases or sequences of letters and digits. All devices joining a network must be programmed to use a Wi-Fi key recognized by the router (or wireless access point). Many home network routers (access points) support only one key that all devices must share in common. Some newer routers can store multiple Wi-Fi security keys instead of one, however, technically allowing local devices to have different key settings (although keeping their keys all the same can simply setup and troubleshooting).
MAC Address RestrictionsMany network routers support a feature called MAC address filtering. Although disabled by default, router administrators can turn this feature on and restrict connections to only certain devices according to their MAC address number. If having difficulty getting a specific device to join the local network (particularly if it is new), check the router to ensure either (a) MAC address filtering is 'off' or (b) the device's MAC address is included in the list of allowed connections.
Loose or Disconnected CablesSometimes the router is turned off, or someone in the family accidentally unplugs power to it. Ensure power strips are switched on and receiving electricity from the outlet, and if applicable, that any Ethernet cables are firmly seated - the connectors should make a clicking sound when snapping into position. If the router can't connect to the Internet but is otherwise operating normally, ensure any modem cables are connected properly.
Overheating or OverloadingDownloading large files or streaming data for long periods causes a home network router to generate heat. In some cases, routers will overheat due to the sustained heavy load. An overheated router will behave unpredictably, eventually disconnecting devices from the local network and crashing. Shutting down the router and allowing it to cool down solves the problem temporarily, but if this issue occurs often, ensure the router has proper ventilation (no vents blocked) and consider moving it to a cooler location.
Home routers can typically handle ten (10) or more connected clients, although if too many devices actively use the network at once, similar overloading problems can result. Even when not physically overheating, the high network activity can cause outages. Consider adding a second router to the network in these cases to better handle the load.
Wireless Signal LimitationsBecause the range of Wi-Fi radio signals is limited, home network connections sometimes fail because a device's radio cannot reach the router's.
Some people also have had their functioning wireless network go offline as soon as anyone in the house turned on the microwave oven. Garage door openers and other consumer gadgets inside homes also can interfere with the signals of Wi-Fi networks, particularly those that use the 2.4 GHz radio bands.
It's also common in cities for the signals of several home Wi-Fi networks to intermingle with each other. Even inside their own home, a person may discover one or more of their neighbor's wireless networks when trying to connect to their own.
To work around these wireless radio interference and range limitations, change the Wi-Fi channel number on the router, or re-position the router. Finally, consider changing your router's name (SSID) if a neighbor is using the same one.
Defective or Outdated Hardware or FirmwareIt's not uncommon for routers to fail after years of regular use. Lightning strikes or other electrical power surges can also damage the circuitry of network equipment. Because they have few moving parts, trying to repair network routers rarely is practical. Set aside some budget for periodically replacing your router (and any other essential network equipment). Also consider keeping some spare cables and a cheap backup router to help with emergency troubleshooting.
Before finally giving up a router, try updating the router's firmware first. Sometimes no firmware update will be available, but in other cases newer firmware may contain fixes for overloading or signaling issues.