Q & A on Physical Addresses on WAN Interfaces Q: I read a CD training material & it indicated that there's NO physical address on a router WAN interface. Is a serial port configured with PPP protocol. I believe each physical interface of a router should have a physical address associated with it right? A: Each connection to a WAN requires a unique address. However, the details vary considerably. In particular, the address may not be present in interface hardware (i.e., the NIC). To understand, think of the telephone system. Although each telephone line is assigned a unique telephone number, the number is NOT stored in the telephone. Other WAN technologies use the same scheme -- although each connection has a unique address, the address need not be stored in the rotuer's interface.