SSID is short for service set identifier. In layman’s terms, an SSID is the name for a Wi-Fi network.
People typically encounter an SSID most often when they are using a mobile device to connect to a wireless network. For example, if you take your laptop to the coffee shop and attempt to connect to the local Wi-Fi, your screen will display a list of SSIDs — the names of all the networks that are within range for your device. You’ll select the name of the local coffee shop network and enter the password (if necessary) to connect.
How to Change the Default Wireless Network Name (SSID) and Password
SSIDs can be up to 32 alphanumeric characters long. They are also case-sensitive; “HOME” is a different network than “home.”
Many router manufacturers set up their devices to use a generic name by default (often the make and model of the router). However, security experts recommend changing the default name and password. This makes it more difficult to hack into the network, and it also makes it less likely that two networks with the same SSID will be within range of each other.
Quick Tip: The SSID can be changed in the software configuration pages for your wireless modem. The modem manufacturer will provide a common IP address that you enter in the address bar of a Web browser to access settings, using a generic username and password. Once logged in, you can then change the network name (SSID) and password for your network. Alternatively, you can contact your ISP technical support team to walk you through the steps or have the network name and password changed for you
802.11 WLAN Standards
The IEEE 802.11 WLAN architecture standards specify that the SSID be attached to the header of packets sent over a wireless local-area network (WLAN). This helps to ensure that data is being transmitted to and from the correct network.
The SSID differentiates one WLAN from another, so all access points and all devices attempting to connect to a specific WLAN must use the same SSID to enable effective roaming. As part of the association process, a wireless network interface card (NIC) must have the same SSID as the access point or it will not be permitted to join the basic service set (BSS) — a component of the IEEE 802.11 WLAN architecture.
An SSID is necessary for a secure network, but on its own, it doesn’t do much to make a network more secure. An SSID can be sniffed in plain text from a packet and most access points broadcast the SSID multiple times per second within the body of each beacon frame. A hacker can easily use an 802.11 analysis tool to identify the SSID.
Some network administrators turn off SSID broadcasting in an attempt to “hide” a network, but experts say that this can actually make a WLAN more vulnerable to attack.
Using Multiple SSIDs
Users can assign more than one SSID to an access point. Using multiple SSIDs allows users to access different networks, each with different policies and functions, increasing the flexibility and efficiency of the network infrastructure. For example, a hotel owner may set up one network for guests and one network for employees. The two networks might use the same physical infrastructure, but they would have two different SSIDs, which would help prevent guests from being able to access sensitive information contained on the hotel servers.