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To subscribe or unsubscribe via the World Wide Web, visit https://lists.isc.org/mailman/listinfo/dhcp-users or, via email, send a message with subject or body 'help' to dhcp-users-requ...@lists.isc.org You can reach the person managing the list at dhcp-users-ow...@lists.isc.org When replying, please edit your Subject line so it is more specific than "Re: Contents of dhcp-users digest..." Today's Topics: 1. Re: Curious behaviour with expired/abandoned leases not being given out (Christopher Causer) ---------------------------------------------------------------------- Message: 1 Date: Wed, 11 Mar 2020 12:18:38 +0000 From: Christopher Causer <christopher.cau...@it.ox.ac.uk> To: Users of ISC DHCP <dhcp-users@lists.isc.org> Subject: Re: Curious behaviour with expired/abandoned leases not being given out Message-ID: <20200311121838.dxat7p2dfkmpv...@cinethon.oucs.ox.ac.uk> Content-Type: text/plain; charset=us-ascii On Tue, Mar 10, 2020 at 10:06:35AM -0400, perl-list wrote: > I've seen situations where one client can continuously DHCPDECLINE > every address that is allocated essentially marking entire pools > abandoned. It goes like this: Interesting thought. There are indeed many DHCPDECLINEs in the logs. However, this isn't limited to one client; there are 349 distinct MACs in total in the last hour. The only connection is they're almost exclusively Apple devices (MBP, iPhone etc). These stations usually DHCPREQUEST their second offer. A colleague suggested that something like Bonjour Sleep Proxy may be the underlying cause. I was doubtful given that would affect all devices doing an arp rather than Apple devices. However, after turning on client isolation on one of the subnets we are no longer seeing DHCPDECLINEs and the touched percentage is indeed going down for that subnet. So in summary thank you for the helpful replies. Although I'm still not certain as to the underlying cause of the issue, we now have an easy to implement workaround. Christopher ------------------------------ Subject: Digest Footer _______________________________________________ dhcp-users mailing list dhcp-users@lists.isc.org https://lists.isc.org/mailman/listinfo/dhcp-users ------------------------------ End of dhcp-users Digest, Vol 137, Issue 3 ******************************************