SSID

June 6th, 2008

SSID – Service Set Identifier

by Zaib Kaleem

A SSID (service set identifier) identifies the wireless network and the SSID for your wireless WLAN card must match the SSID for any access point that you want to connect with. If the value does not match, you are not granted access to the network. Each SSID can be up to 32 characters long and is case-sensitive.

Multiple Access Points with the Same SSID

Muliple access points can have the same SSID and in most cases this configuration is known as an extended service set (ESS) when the two access points are connected to the same wired network. Sharing the same SSID can be an issue if the two access points are in close proximity but are not owned or part of the same wired network. In this case end user devices may connect to the incorrect SSID.

How to Discover Non-Broadcasting SSIDs

If the SSID is not being broadcasted, finding the hidden SSID is possible but requires special software that is able to look at wireless data frames to extract the SSID. There are many commercial products that have this RFMON capability and several open source products such as Kismet.