This document provides information on how to diagnose and resolve connectivity related issues on wireless Routers, ADSL Broadband Cable Modems, and Wireless Gateways.

Even though there are many things that can prevent your wireless router/gateway from operating trouble-free, most problems can be attributed to simple contributing factors like: Obsolete or corrupted firmware, Incorrect data transmission rate settings, Incompatible encryption/security settings, Excessive RF interference, Highly degraded/attenuated radio signal, SSID broadcast issues, Incorrect/conflicting networking parameter settings, Data packets not getting past a firewall, or Use of conflicting radio channels.

If you are experiencing problems with your wireless router, we suggest you start troubleshooting with the following:

• Verify that your Router is Hooked-up Properly and Powered On: Check the power, LAN and wide area network (WAN) uplink cables and confirm that they are connected properly. Look for visibly damaged (torn, punctured, or kinked) data cables and broken/loose (RJ45/RJ14/RJ11 or BNC) connectors. Check the LEDs on your wireless router/gateway or your cable modem to see if any of them are blinking abnormally, or flashing red/yellow. Consult your product manual to remedy any such abnormalities found.
  
• Check your Router's Firmware/Software Version, and Upgrade if Needed: If you have power cycled your router, and while apparently in normal state, it fails to connect with any of your client devices (e.g. your Laptop, PDA, or your Nintendo DS / WFC, etc.); check with the router manufacturer to see if they have a firmware update available. While most routers allow for easy upgrade to their firmware (EEPROMs) these days, your should be aware of the rare possibility that a failed/corrupted firmware upgrade may possibly render your router completely unusable. Should that happen, you might have to request a replacement router from the manufacturer.
  
• Set your Wireless Router to Operate in 802.11b or Mixed Mode: If you have a wireless device that does not support faster wireless standards (11a or 11g, etc.), consider configuring your router to operate in 802.11b (wifi) or in mixed mode. A wireless gadget designed for the WiFi (IEEE 802.11b) standard will not interoperate with wireless routers/gateways that are setup to operate exclusively in faster (802.11a or 802.11g) modes.
  
• Poor RF Signal Strength: Many RF clients now have a built-in signal strength indicator. If your wireless client is receiving a weak (or a highly degraded) RF signal, or a radio signal that has extremely poor signal to noise ratio; consider one of the following options: Moving your wireless client device closer to your wireless router, Removing any metallic or organic substances that may be either shielding or absorbing the RF signal, and installing an add-on antenna on your radio transmitter –provided in doing so you will not be pumping out more RF power than what is allowable per FCC Part 15 Regulations. Should you consider installing an add-on antenna, you should do so only after carefully considering potentially harmful effects of prolonged exposure to excessive RF radiations.
  
• Your Wireless Client Does Not Detect Router's SSID: It may be a result of your router having been configured to operate in stealth mode -i.e. to operate in disable SSID broadcast mode. You can either enable SSID broadcast temporarily or manually enter your router’s SSID in your wireless client, and try again.
  
• MAC Filtering: If you have MAC Filtering turned on in your wireless router, you need to explicitly enter (i.e. white list) your wireless gadgets’ MAC Addresses into your router’s allowed list.
  
• Wireless Channel Conflicts: You may have other (unknown) wireless devices operating in the general vicinity of your WLAN that may also be broadcasting on the channels that your wireless router may be setup to use. If so, it can interfere with your RF communications and possibly prevent you from having a reliable wireless link to your router. Set your router to use a different channel (and do not forget to reconfigure your wireless client devices to use that new channel as well), and try again.
  
• Resolve any Networking Parameter Settings Related Conflicts: In stead of using DHCP, try setting your router to use Static IP Addresses and assign to your wireless client a non-conflicting (unused) Static IP address. Make sure that your subnet masks, DNS host settings and default gateway settings in your TCP/IP applet are also setup correctly. One of the easiest ways to find out your network address assignments is to run IPCONFIG/ALL command in a DOS (Command line) window. Here is how to do it: Click on Start button in the lower left-hand corner of your Windows PC, and click on Run. Then Type-in cmd into the edit box and press Enter on your keyboard. Click inside the Command/DOS Window, Type IPCONFIG/ALL and press Enter. Check your network address, netmask, and default gateway settings for any conflicts or errors.
  
• Temporarily Disable Wireless Encryption: To eliminate possible complications due to a mismatch in the encryption method (WPA vs. WEP, etc.), or due to a encryption key type (ASCII, Hexadecimal, or Passphrase WEP key) mismatch, temporarily configure all your wireless devices to transmit in plain-text -i.e. without using any type of data encryption. If you are able to establish a wireless link while operating in clear / unencrypted mode, look into identifying (and resolving) any mismatch in the encryption method and/or the type of encryption key being used on your wireless router and your wireless client.

If your wireless client is able to see and successfully associate/connect with your wireless router/gateway, but fails to communicate any data through it; you may have an application layer problem. Look into your Firewall settings to see if you are running afoul of one of its security settings or Access Control Lists -thereby causing it to block all communications from your wireless client.