how to force new leases (not renewals)
Simon Hobson
dhcp1 at thehobsons.co.uk
Tue Jan 26 08:07:13 UTC 2010
Justin DeMaris wrote:
>One very unconventional trick we have used to push out lease changes
>is to do shut/no shut on the switch port interface. This only works
>for devices wired directly to the switch with no active
>amplification (hub, etc) in between but it makes windows and linux
>do a full new lease since it feels like it got unplugged
Does it still do that ? Some modern clients do tricks like checking
if the MAC address of the default router is still the same to
determine if they are on the same network after bringing up an
interface.
Back to the original issue, I'm sure it's been reported before -
WIndows clients changing their address but not recognising any
changed options.
If the OP has enough address space then they could simply move the
range completely (overnight or at another quiet time) which would
force all clients to get a new address. Also, either in conjunction
with that or on it's own, progressively reduce lease times so that
all clients will expire their leases overnight. Thinking about it, if
you don't mind a complete outage for a few minutes at a quiet time,
get the lease length down to (say) 5 minutes, then shut down the DHCP
service for 5 minute - that is guaranteed to make all leases expire
even if a client is up permanently.
--
Simon Hobson
WANTED: "Software CD ROM Kit" for Canon CLBP 360-PS printer (Canon
part no RH6-3612, or possibly RH6-3810, or RH6-3610 might do). I've a
dead HD and need this CD so I can replace the disk and re-install the
printer OS on it. If anyone knows where I might get hold of one I'd
be grateful - requests to Canon drew a blank, it's been out of
support for years.
Alternatively, if anyone has one of these and would let me image
their hard disk ...
Visit http://www.magpiesnestpublishing.co.uk/ for books by acclaimed
author Gladys Hobson. Novels - poetry - short stories - ideal as
Christmas stocking fillers. Some available as e-books.
More information about the dhcp-users
mailing list