Basic question on private wifi network

[AmLost]

If replace a computer I had with another, will its network IP address, which is given by the router to all devices (such as ip addresses ending differently, but only in the network), be given to a new computer? Or will that new computer get a completely new unrelated network IP address? Or does it change after awhile, and they all get reused? Because, they are all under the same public IP address... Right?DHCP is turned on if it matters...

 

[kanewolf]

DHCP will allocate address on a first-come first-served basis. So after the router reboots the first device to ask for an IP address gets .002 (or .010 or .050 or whatever you set the DHCP range to be). If your computer gets the first address on Monday it will generally stay that address for as long as it is up and connected. If it is off for an extended period of time (usually days) then some other device could get that first address. The simplicity of DHCP is that usually you don't care what IP address a specific device gets. As long as it is unique then everything works.
If you always want the same address there are two ways to do it. 1 set a static IP on the device instead of DHCP. 2 create an IP reservation in your DHCP device so that when a specific MAC (unique hardware ID) requests a DHCP address it ALWAYS gets the same one.