what is ip address and what decides it?

hello frens.. may ce it is simple one but i would like to ask u that what is ip address and what decides it. it comes with when pc was purchased like imei number of mobile or it is generated when connectd to the internet network? if it is coonected with the internet connection like adsl. wi fi etc then i have a question that does it change as the pc uses different connections? for example today i used the wi fi of company A and after few days i use net using another wi fi due to some reason then will my pc have same ip address what ever connection i use or will it be diffrent conection to connection.?
i have kept my question with elaboration so i hape u will suggest me in the same way


regards

Hi darkcloud, IP addresses are assigned by DHCPs. DHCP services usually run on routers, access point,...
A DHCP will assign you the first available IP or a fixed IP if there is a rule to match your MAC address.
So if you connect to a network in different places you will most likely get a different IP address. Also if you stay in the same place and connect using a different adapter, chances are you get a different IP address if there's more than 1 person connecting.
A MAC address on the other hand is specific for the adapter (wifi card or lan) and that does not change.

Hope that wasn't too confusing!

thank u for the reply mr alberto. it means if i use different connection depending on my convenience then i will get different ip addres but fot the same connection i will have same ip? am i right

Well, if you always use the same connection you MIGHT get the same IP address. If you are the only one connecting then you will always get the same one, but if there's more than one device connecting, the address you used last time might already be in use and you would get a new one.
But are you concerned with LAN addresses (192.168....) or more generally the address you see when you log onto sites like whatismyip[dot]com?