DHCP question

Soogs · 17 Dec 2020 at 10:57

Do devices always try to get the last IP address they were assigned?

I've set my lease times to 60 seconds in the hopes that the devices will start using address back at the start of the pool range but so far no matter how long i leave devices off for they claim their last used IP.

is there a way to force a refresh of this (using an Edgerouter X)

neil_g · 17 Dec 2020 at 11:05

try clearing the lease, not an option on my ER GUI but the CLI command is:

clear dhcp lease ip <ip_address>

bremen1874 · 17 Dec 2020 at 11:13

Why would you care?

Where the IP matters I have them on reservations, for the rest of them why worry?

pepp77 · 17 Dec 2020 at 11:16

Yes a device will always ask for the same IP it had previously via DHCP when it requests DHCP, if its available it will get it, if not it gets a new one.

Soogs · 17 Dec 2020 at 11:25

I've figured it out... i made the pool smaller and forced new IPs on devices.

why? OCD... i had numbers all over the gaff and it was annoying me.

I am making the important (or maybe all of them static now)

Soogs · 17 Dec 2020 at 11:25

pepp77 said:
Yes a device will always ask for the same IP it had previously via DHCP when it requests DHCP, if its available it will get it, if not it gets a new one.

thanks

Caged · 17 Dec 2020 at 11:34

Don't get hung up on having devices get sequential addresses, it will drive you mad when you finally have IPv6 turned on.