Devices are identified by their owners and authorization to network two or more devices is based on device ownership. Data structures such as address books can store information about an owner of a device and maintain an entry indicating that a particular entry identifies the owner of the device. Other entries in the address book are contacts of the owner. A host device can authorize a client for communication with the host based on a relationship between the owner of the client and the owner of the host as indicated by the presence of the contact information of the client's owner in the host's address book. Devices and can enable communication and sharing of services and levels of access permissions based on the relationship of the owners' of the respective devices.