apngss@yahoo.com wrote:

> I want to ask who assigns the IP address to a machine that connects to
> the Internet? The ISP, the network card (i.e. MAC address??), or the
> router?
>
> It seems like my IP address is fixed everytime connected to the
> Internet, it seems very unsecure because it allows hackers track the
> computers more easily.
>
> I thought the IP address should be dynamic, and each time when we
> connect to the Internet should have different IP address.
>
> Is there a way that makes the IP address in my machine becomes dynamic?

The IP address is assigned by the ISP. Normally, with DHCP, you "own" the
address for the duration of the lease time. Part way through the lease,
your computer (or router) will attempt to renew the address. This means
that as long as you stay connected, you will likely retain the same
address. Your computer caches the address, so that if you turn it off and
later, back on, it will request the same address, if available. You might
be able to get a new address, if you release the IP and then get another
address, however that may not always work, as your ISP may also cache the
IP & MAC address pair, for at least the duration of the lease. If that's
the case, your only options for forcing a change, is to change the MAC
address of your hardware, or leave your equipment turned off long enough
for the lease to expire and the address be assigned to someone else.