IP addresses are similar to postal addresses as each host has an ip address of its own. To communicate with another host, one must know the other host's ip address. Machines must know the ip address of another host as every machine has several hosts similar to a locality that has several residences, without knowing the address of a person, one may get lost, similarly without knowing the ip address of the host, the communication can't happen.
IP addresses act like unique identifiers, similar to postal addresses for hosts. To establish communication, machines must be aware of the target host's IP address. This necessity mirrors the way we need an address to locate someone in a neighborhood. Without the specific IP address, effective communication between machines is not possible.
