Computer networks

Question

How it is possible for computer to have multiple ip address at different instance of time?

Answer 1

The public IP addresses are not statically allocated to a computer but are leased dynamically by a DHCP server which sits somewhere in the network managing allocation of IP addresses.When a lease runs out the computer makes another DHCP request which typically extends the lease for same IP address. However if the IP address was allocated to someone  else in the meantime then a new DHCP address is offered.

Comments

Addition: Even at a same instance a machine can have different IPs by having additional NICs(Network Interface Cards). Routers generally have more than one IP depending on how many interfaces they are connected to. Actually, IPs are not given to machines or devices but to the interfaces they are connected with. So it means, your wire/wireless network has IP but not your desktop/mobile.