2.2 NetworkManager and Security
NetworkManager distinguishes two types of wireless connections, trusted
and untrusted. A trusted connection is any network that you explicitly
selected in the past. All others are untrusted.
Trusted connections are identified by the name and MAC address of the
access point. Using the MAC address ensures that you cannot use a different
access point with the name of your trusted connection.
If no wired connection is available, NetworkManager scans for available
wireless networks.
If multiple trusted networks are found, the most
recently used is automatically selected. If all are untrusted, NetworkManager waits for
your selection.
If the encryption setting changes but the name and MAC address remain
the same, NetworkManager attempt to connect, but it first asks you to confirm the
new encryption settings and provide any updates, such as a new key.
In a system with a wireless connection only, NetworkManager does not automatically
start the connection during boot. You must login first to
establish a connection. If you want to make a wireless connection accessible
without login, configure the trusted connection with YaST. Only
wireless connections configured with YaST are sufficiently credible for
NetworkManager to use them during boot.
If you switch to offline mode from using a wireless connection,
NetworkManager blanks the ESSID. This ensures that the card is really unassociated.