This flag lets you limit which networks the client can connect through. When this flag is set, the client can use only the specified IP address to connect to a network.
You can set either an IPV4 address (for example, 192.168.0.2) or IPV6 address (for example, 1:2:3:4::1) that represents the local IP address you want to communicate through.
When this flag is not set, the client can connect to any available network.
Setting the value to NULL will result in setting it to the default value.