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I have ~100 clients on my LAN.

When they get turned on simultaneously many seem to get assigned the same IP addresses. - I use dhcp

How can I get them get ubuntu to release all the currently assigned IPs address in my LAN (some clients are still stuck with the same IP address) and have the clients renew unique IP addresses?

Thanks Ubuntu gurus.

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Do you have enough IP's set in DHCP? – Mitch Feb 28 '14 at 7:18
Yes, I have 200 IPs made available. These clients seem to randomly lose their MAC addresses (incomplete) .... Does that symptom sound familiar? – Ben Mar 1 '14 at 15:01

It is not possible to force clients to release their IP's. The client could release its own dynamic IP (ex: sudo dhclient -r eth0)

Try make small release time, ISC DHCP server has such configuration. Default is:

default-lease-time 86400;
max-lease-time 86400;

ie 24h, Try with default-lease-time 1800 ie 30min or even less.


If you using other DHCP server then ISC (or DSL routers), Most of them provide option to set Release Time.

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