Re: DHCP timeout is too short for this college network

[Sven Nielsen <post svennielsen de>]

Ask the dhcp team on your campus why they are giving away DHCP leases
for 3! days (286274 seconds):

> >> Jan 10 21:40:12 DHCPACK of 149.106.215.247 from 149.106.192.253
> >> Jan 10 21:40:13 bound to 149.106.215.247 -- renewal in 286274
seconds.

Maybe the DHCP server is continously short on free IP addresses because
many addresses that are actually free, are still bound to clients that
connected e.g. 2 days ago. (It surely gets hundreds of requests every
day.) Might be that every time it tries to process a DHCP requests, it
has no addresses left and then has to go through all addresses manually
by way of pinging them to find out which ones are not in use anymore
before it finds a free address. This might easily be one of the causes
for the long delays.

Also, perhaps the DHCP configuration should be divided into two address
pools (it it isn't already), one address pool for resident computers
(Destkop PCs and laptops of university staff), and another pool for
student laptops (unknown DHCP clients).

Then the resident address pool can keep the policy of 3-day-lease time
while short-lived clients like students laptops and WLAN mobiles could
be shortened to a dhcp lease of 1 hour or even less.

cheers,
sven