IP swapping for network restart or reboot for ubuntu client

[Wayne Gemmell | Connect]

It is triggered with a netplan apply specifically in our case, no Cisco in
sight.




On Tue, 14 Jun 2022 at 15:57, perl-list <perl-list at network1.net> wrote:

> Is this by chance in conjunction with Cisco's DHCP Proxy configuration?
> What we saw there was that the Cisco device inserted a RELEASE whenever a
> DISCOVER happened.  The RELEASE was so close (< 5ms) on top of the
> subsequent DISCOVER that the DHCP server, in failover, did not have time to
> propagate the address being freed up and so a second address would be
> configured.  We had to get Cisco to insert a delay between the RELEASE and
> the DISCOVER of some length (though I don't remember the details).
>
> ----- Original Message -----
> > From: "Wayne Gemmell | Connect" <wayne at connect-mobile.co.za>
> > To: "Users of ISC DHCP" <dhcp-users at lists.isc.org>
> > Sent: Tuesday, June 14, 2022 9:50:00 AM
> > Subject: Re: IP swapping for network restart or reboot for ubuntu client
>
> > We do run a primary fail-over setup and haven't tested it again as a
> standalone
> > host.
>
> > On Tue, 14 Jun 2022 at 15:41, Kraishak Mahtha < [ mailto:
> kraishak.edu at gmail.com
> > | kraishak.edu at gmail.com ] > wrote:
>
> >> Hi Wayne,
> >> Thanks for sharing the link,
>
> >> I have observed that I am seeing this IP switch only if it is in a
> >> primary-failover mode whereas if we run the DHCP server standalone we
> do not
> >> see any issue and the IP is being constant, by any chance did you try
> this case
>
> >> On Tue, Jun 14, 2022 at 2:56 PM Kraishak Mahtha < [
> >> mailto:kraishak.edu at gmail.com | kraishak.edu at gmail.com ] > wrote:
>
> >>> * Observed in the Ubuntu version 20.04
>
> >>> On Tue, Jun 14, 2022 at 2:39 PM Kraishak Mahtha < [
> >>> mailto:kraishak.edu at gmail.com | kraishak.edu at gmail.com ] > wrote:
>
> >>>> Hi all,
> >>>> We are experiencing weird behavior with ISC's DHCP version 4.4.2.
> When the
> >>>> Wintel(windows) clients use the ISC DHCP servers that are operating
> in a
> >>>> primary-failover mode, then reboot or a renewal does not see any
> address
> >>>> shuffle. When the Ubuntu clients use the ISC DHCP servers, we are
> observing a
> >>>> periodic IP Address shuffle upon a reboot. This shuffling is not
> observed when
> >>>> we are using a Microsoft DHCP solution. We are interested to know if
> this issue
> >>>> is a known issue in the ISC database. If there is a workaround to
> resolve this
> >>>> issue, please let us know.
>
> >>>> Thanks in Advance
>
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