Service Set Identifier (SSID) is the primary name associated with an 802.11 wireless local area network (WLAN) that includes home networks and public hotspots. Client devices use this name to identification and to join wireless networks. For example, while trying to connect to a wireless network at work or school named guest_network you see several others within range that are called something entirely different names. All the names you see are the SSIDs for those networks. On home Wi-Fi networks, a broadband router or broadband modem stores the SSID but administrators can change it. Routers broadcast this name to help wireless clients find the network.
The Service Set Identifier (SSID) is a case-sensitive text string that can be as long as 32 characters consisting of letters or numbers or a combination of both. Within these rules, the SSID can say anything. Router manufacturers set a default SSID for the Wi-Fi unit, such as TP_LINK, D_LINK, JIO_FI or just DEFAULT. Since the SSID can be changed, not all wireless networks have a standard name like that.
Uses of SSID by devices –
Wireless devices like phones, laptops etc scan the local area for networks broadcasting their SSIDs and presents a list of names. A user can join a new network connection by picking a name from the list. In addition to obtaining the network’s name, the Wi-Fi scan also determines whether each network has wireless security options enabled or not. In most cases, the device identifies a secured network with a lock symbol next to the SSID.
Most wireless devices keep track of the different networks a user joins as well as the connection preferences. Users can also set up a device to automatically join networks having certain SSIDs by saving that setting into their profiles. In other words, once connected, the device usually asks if you want to save the network and reconnect automatically in future.
Most wireless routers offer the option to disable SSID broadcasting to improve Wi-Fi network security as it basically requires the clients to know two passwords, the SSID and the network password. However, the effectiveness of this technique is limited since it’s fairly easy to get the SSID from the header of data packets flowing through the router. Connecting to networks with disabled SSID broadcast requires the user to manually create a profile with the name and other connection parameters.
Problem with SSIDs –
- If there is no wireless security options enabled on a network then anyone can connect to it by knowing only the SSID.
- Using a default SSID increases the chances that another nearby network will have the same name which can confuse wireless clients. When a Wi-Fi device discovers two networks with the same name, it will prefer and may try auto-connecting to the stronger radio signal, which might be the unwanted choice. In the worst case, a person might get dropped from their own home network and reconnected to a neighbor’s who does not have login protection enabled.
- The SSID chosen for a home network should contain only generic and sensible information. Some names (like HackMyWIFIIfYouCan) unnecessarily provoke thieves to target certain homes and networks over others.
- An SSID can contain publicly visible or offensive language or coded messages.