The release parameter is used to remove the DHCP settings for your
computer.
The renew parameter is used to update the DHCP settigns for your
computer.
These are some of the steps that are taken when you 'repair' a network
connection in the control panel, network connections. The repair also
performs a flushdns and registerdns.
The release/renew options are used to force your computer to reregister
with the DHCP server before your lease has expired. This can be
beneficial if the DHCP server has been modified, the DNS servers have
changed, WINS servers, etc.
Also if you are disconnecting your computer from one domain and placing
it on a different domain it is a good idea to use the release and renew
commands by doing the following:
close all programs, run IPconfig /release, connect the computer to the
new domain, and then run an IPCONFIG /renew.
This will keep your computer from freezing up or slowing down
dramatically when looking for files, servers, etc from the old domain
after being attached to the new domain.
