SSID (Service Set IDentifier) is an identification beacon -kind of like an airplane transponder -that continually announces that a wireless device (an Access Point, Wifi Gateway, Wireless Bridge or a Wireless Router, etc) is on-air. SSID alerts others that a wireless device is available.

However, broadcasting SSID is like having your wireless AP/Router continually wave (day and night) at all those that may be passing-by, and inviting them to take a shot at it. Kind of painting a bulls-eye on your wireless AP/gateway so that others can easily find it -just in case they would not mind breaking into your wireless LAN.

Disable SSID Broadcast unless you are setting up a wifi hotspot that is meant to be open to all. Practice Safe WiFi -Keep your SSID private, don't broadcast it to the world; and hardcode your AP/Router's SSID into all your client gear. Doing so in itself will not make your WLANs completely impenetrable, but it will greatly improve your chances of warding off unwarranted attention.

Disabling SSID broadcast essentially renders your Access Point invisible to all those that may be scanning (using wireless sniffer programs) or war-driving around your neighborhood looking for vulnerable WLANs -except for those that may already know its (SSID) identity.

Most wireless products are sold/preconfigured with a (rather well known) default SSID. Considering that there are only a handful of companies that make hardware for wireless networking, your wireless gadget may be preconfigured to use one of the following (factory-default) SSIDs:

1. 101 : Factory default SSID on 3Com wireless products
   
2. Compaq : Factory default SSID on Compaq wireless products
   
3. compex : Factory default SSID on Compex wireless products
   
4. Default : Factory default SSID on D-Link wireless products
   
5. hpsetup : Factory default SSID on HP products
   
6. intel : Factory default SSID on Intel wireless products
   
7. linksys : Factory default SSID on Linksys wireless products
   
8. tsunami : Factory default SSID on Cisco wireless products
   
9. WLAN : Factory default SSID on Addtron wireless products

It would not be a good idea to continue to use any of the above "factory default" SSIDs -even if you are going to disable SSID broadcast on your hardware gear. Just because it may not be actively broadcasting it does not mean it would not respond back if someone were to probe around in its vicinity using one of the aforementioned well-known SSIDs.

Most wireless products would allow you to use up to 32 characters long text string for an SSID -including numbers, upper/lowercase letters, spaces, and dashes. SSIDs labels are cAsE-sENsITivE. We suggest you use a fairly long made-up word that includes upper/lower case letters, numerals and dashes. Make sure you write it down because you will need to enter it when you reconfigure your wlan client computers.

After having disabled SSID broadcasts on your APs and Routers, etc., you must configure wireless adapters on all your client machines to associate with an AP that answers to your newly configured SSID. To prevent your client machines from connecting to any other rogue APs and radiators, you may want to configure them to connect to ONLY known (predefined) SSIDs.