addressing services on any given network there may be multiple hostseach with their own host id but with shared network id for exampleon private home network there may be jasmine' laptop adam' pc home printer smart tv in many ways the network id and host id elements of an ip address are like the postal address for house on street the street may have namefor example coleridge avenue and there may be multiple houses on the street each house has unique numberthus coleridge avenue is uniquely differentiated from coleridge avenue by the house number at this point you may be wondering where the urls you see in your web browser come into play (such as www bbc co ukthese are textual names that actually map to an ip address the mapping is performed by something called domain name system (or dnsserver dns server acts as lookup service to provide the actual ip address for particular textual url name the presence of an english textual version of host address is because humans are better at remembering ( hopefullymeaningful name rather than what might appear to be random sequence of numbers there are several web sites that can be used to see these mappings (and one is given at the end of this some examples of how the english textual name maps to an ip address are given belowwww aber ac uk maps to www uwe ac uk maps to www bbc net uk maps to www gov uk maps to note that these mappings were correct at the time of writingthey can change as new entries can be provided to the dns servers causing particular textual name to map to different physical host localhost there is special ip address which is usually available on host computer and is very useful for developers and testers this is the ip address it is also known as localhost which is often easier to remember