Re: IP swapping for network restart or reboot for ubuntu client

Could be still a similar problem that could be resolved in a similar way.  Is the time between the RELEASE and DISCOVER extremely short (you will probably need to packet capture to find out)?

----- Original Message -----
> From: "Wayne Gemmell | Connect" <[email protected]>
> To: "Users of ISC DHCP" <[email protected]>
> Sent: Tuesday, June 14, 2022 10:01:29 AM
> Subject: Re: IP swapping for network restart or reboot for ubuntu client

> 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 < [ mailto:[email protected] |
> [email protected] ] > 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" < [ mailto:[email protected] |
>> > [email protected] ] >
>>> To: "Users of ISC DHCP" < [ mailto:[email protected] |
>> > [email protected] ] >
>> > 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: [
>> > mailto:[email protected] | [email protected] ]
>> > | [ mailto:[email protected] | [email protected] ] ] > 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: [ mailto:[email protected] | [email protected] ] | [
>> >> mailto:[email protected] | [email protected] ] ] > wrote:

>> >>> * Observed in the Ubuntu version 20.04

>> >>> On Tue, Jun 14, 2022 at 2:39 PM Kraishak Mahtha < [
>>>>> mailto: [ mailto:[email protected] | [email protected] ] | [
>> >>> mailto:[email protected] | [email protected] ] ] > 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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