Set DHCP Lease To One Day

businessuer

Let say person logs in 1 jan at 08:00 hrs and logs out at 1 Jan 17:00 hours.
DHCP Lease set to 2 days.
So will the lease expire at 3 Jan 08:00hrs or 17:00 hrs?

Will setting a lease duration of 1 day be too short because the router have to keep "re-learning" mac addresses? 

Will it affect the hardware? 

mMontana

businessuer said:

Will setting a lease duration of 1 day be too short because the router have to keep "re-learning" mac addresses? 

Will it affect the hardware? 

Both questions: IMO no.

In a low-ratio hardware rotation environment (resident people only, two - to five missing person par day on 50-60 persons) having multiple-day lease won't be an issue. If a device come back at the last hours of lease, it will receive the same address.

In a hi-ratio hardware rotation (bar, restaurant, commercial space, hotel) shorter the lease time, less wasted addresses waiting to expire.

I choose a /23 subnet for the guests wireless network into an hotel with 60 rooms, considering three devices par room plus 180 devices for congress/dining halls (twice the size of the maximum capacity. Lease time 4 hrs.

PeterUK

You can set the Lease time to 2 minutes and it be fine.

The client can ask for a renew by DHCP by unicast before the lease time and before the client renews by broadcast which reset the lease time.

businessuer

Sorry but why is a broadcast necessary?

PeterUK

businessuer said:

Sorry but why is a broadcast necessary?

Well you need a broadcast to get a IP but if you mean for renewing a IP the client may not send a unicast request and waits till rebinding which is a broadcast and it can ask for a reply from the server to be a broadcast or unicast.

More about DHCP here:

https://lazyadmin.nl/home-network/dhcp-lease-time/

Zyxel_Melen

Hi @businessuer,

Just like @PeterUK's explaination and @mMontana's suggestion, you can depend on your envirement to set suitable lease time, DHCP Server pool and subnet.