This sounds like dhclient bug
https://bugzilla.redhat.com/show_bug.cgi?id=1093803
The internal DHCP plugin (from systemd's network library) doesn't have
issue with resetting time.
On Wed, 2016-06-08 at 12:14 +0300, matti kaasinen wrote:
> Hi!
>
> I got into same conclusion as as Eli (http://billauer.co.il/blog/2012
> /10/dhcp-ip-ntpdate-rtc/) that dhclient notices that time has
> advanced over lease "expire" moment after time jump due to ntpdate.
> As a consequence it rejects old IP and claims new one. I tried more
> elegant way to get this solved so that I first check difference
> between local and NTP time. If it is big enough, I switch from dhcp
> mode to manual mode using the IP from dhcp lease. Then I run ntpdate
> and switch back to dhcp mode. Sound elegant (and complicated), but
> really from logs it seems pretty the same as what Eli got.
>
> This works somehow, IP does not change change. However, Avahi does
> not tolerate this quite perfectly. It usually does, but sometimes it
> gets confused and does not discuss with avahi-browse/avahi-discover.
> This can quite well come from the fact that I need to run dhclient-
> enter-hook to keep IPv4LL address.
>
> In fact, wouldn't this issue been fixed in dhclient just by
> monitoring lease trials: It should not reject the old lease if there
> are no refresh trials before time exceeds the "expire" moment. I hope
> you do something like that in NM-dhclient. I also hope that you could
> figure out some policy to maitain IPc4LL address when dhcp client
> gets lease.
This sounds like dhclient bug
https://bugzilla.redhat.com/show_bug.cgi?id=1093803
The internal DHCP plugin (from systemd's network library) doesn't have
issue with resetting time.
Thomas
>
> Thanks,
> Matti
>
> 2016-05-17 10:15 GMT+03:00 matti kaasinen <matti kaasinen gmail com>:
> > Hi!
> > Some more information - lease log from board after re-installation
> > and dhcp server log:
> > ================================
> > lease {
> > interface "eth0";
> > fixed-address 111.111.3.15;
> > option subnet-mask 255.255.252.0;
> > option dhcp-lease-time 7200;
> > option routers 111.111.1.2;
> > option dhcp-message-type 5;
> > option dhcp-server-identifier 111.111.1.2;
> > option domain-name-servers 111.111.1.2;
> > option broadcast-address 111.111.3.255;
> > option domain-name "domain.fi";
> > renew 5 2016/03/11 14:46:10;
> > rebind 5 2016/03/11 15:41:49;
> > expire 5 2016/03/11 15:56:49;
> > }
> > lease {
> > interface "eth0";
> > fixed-address 111.111.3.15;
> > option subnet-mask 255.255.252.0;
> > option routers 111.111.1.2;
> > option dhcp-lease-time 7200;
> > option dhcp-message-type 5;
> > option domain-name-servers 111.111.1.2;
> > option dhcp-server-identifier 111.111.1.2;
> > option broadcast-address 111.111.3.255;
> > option domain-name "domain.fi";
> > renew 5 2016/03/11 14:44:36;
> > rebind 5 2016/03/11 15:41:52;
> > expire 5 2016/03/11 15:56:52;
> > }
> > lease {
> > interface "eth0";
> > fixed-address 111.111.3.11;
> > option subnet-mask 255.255.252.0;
> > option routers 111.111.1.2;
> > option dhcp-lease-time 7200;
> > option dhcp-message-type 5;
> > option domain-name-servers 111.111.1.2;
> > option dhcp-server-identifier 111.111.1.2;
> > option broadcast-address 111.111.3.255;
> > option domain-name "domain.fi";
> > renew 2 2016/05/17 06:39:51;
> > rebind 2 2016/05/17 07:37:25;
> > expire 2 2016/05/17 07:52:25;
> > }
> > ====================
> > As you can see, board gets two leases pretty rapidly, then it gets
> > NTP time and new lease with new IP. Is this problem coming from the
> > fact that when board gets NTP time, it notices that time is over
> > expiration time and it has to drop its lease.
> >
> > I suppose that this is what Connman handles differently.
> >
> > Communication log from dhcp server:
> > ===========================
> > May 17 08:49:33 ubuntu1 dhcpd: DHCPDISCOVER from 84:eb:18:96:a2:14
> > via eth1
> > May 17 08:49:34 ubuntu1 dhcpd: DHCPOFFER on 111.111.3.15 to
> > 84:eb:18:96:a2:14 via eth1
> > May 17 08:49:34 ubuntu1 dhcpd: DHCPREQUEST for 111.111.3.15
> > (111.111.1.2) from 84:eb:18:96:a2:14 via eth1
> > May 17 08:49:34 ubuntu1 dhcpd: DHCPACK on 111.111.3.15 to
> > 84:eb:18:96:a2:14 via eth1
> >
> > May 17 08:49:36 ubuntu1 dhcpd: DHCPREQUEST for 111.111.3.15 from
> > 84:eb:18:96:a2:14 via eth1
> > May 17 08:49:36 ubuntu1 dhcpd: DHCPACK on 111.111.3.15 to
> > 84:eb:18:96:a2:14 via eth1
> >
> > May 17 08:52:16 ubuntu1 dhcpd: DHCPDISCOVER from 84:eb:18:96:a2:14
> > via eth1
> > May 17 08:52:16 ubuntu1 dhcpd: ICMP Echo reply while lease
> > 111.111.3.15 valid.
> > May 17 08:52:16 ubuntu1 dhcpd: Abandoning IP address 111.111.3.15:
> > pinged before offer
> >
> > May 17 08:52:24 ubuntu1 dhcpd: DHCPDISCOVER from 84:eb:18:96:a2:14
> > via eth1
> > May 17 08:52:25 ubuntu1 dhcpd: DHCPOFFER on 111.111.3.11 to
> > 84:eb:18:96:a2:14 via eth1
> > May 17 08:52:25 ubuntu1 dhcpd: DHCPREQUEST for 111.111.3.11
> > (111.111.1.2) from 84:eb:18:96:a2:14 via eth1
> > May 17 08:52:25 ubuntu1 dhcpd: DHCPACK on 111.111.3.11 to
> > 84:eb:18:96:a2:14 via eth1
> >
> > May 17 09:39:51 ubuntu1 dhcpd: DHCPREQUEST for 111.111.3.11 from
> > 84:eb:18:96:a2:14 via eth1
> > May 17 09:39:51 ubuntu1 dhcpd: DHCPACK on 111.111.3.11 to
> > 84:eb:18:96:a2:14 via eth1
> > ==========================
> >
> > I hope someone can sort out what goes wrong / howto fix it.
> > Thanks,
> > Matti
> >
> >
> > 2016-04-25 21:33 GMT+03:00 matti kaasinen <matti kaasinen gmail com
> > >:
> > > It is dedicated dhcp server for local area network called dhcpd3.
> > > I don't know how many free leases it has, but it do have very
> > > much free addressing space. I don't beleave server changes addres
> > > for lack of addresses. There are only couple of workstations
> > > (below 10) using dhcp addressing and basically their address
> > > never changes.
> > >
> > > 2016-04-25 16:58 GMT+03:00 José Queiroz <zekkerj gmail com>:
> > > >
> > > >
> > > > 2016-04-25 2:24 GMT-03:00 matti kaasinen <matti kaasinen gmail
> > > > com>:
> > > > > dhcpd3
> > > > >
> > > > >
> > > > Sorry. I didn't make myself clear.
> > > >
> > > > Which device is your DHCP server? A router (maybe wifi)? A
> > > > dedicated/generic router? A server?
> > > >
> > > > How many free leases the DHCP server have, now?
> > > >
> > > >
> > > > _______________________________________________
> > > > networkmanager-list mailing list
> > > > networkmanager-list gnome org
> > > > https://mail.gnome.org/mailman/listinfo/networkmanager-list
> > > >
> > > >
> > >
> >
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