pfSense WAN interface doesn't recover from modem being disconnected

jgauthier · Sep 18, 2021, 7:50 PM

Hi everyone,

I am running pfSense 2.5.2 . I recently upgraded to my ISP's (Videotron in Quebec-CA) new tech stack, they call Helix. Helix is based on COMCAST Xfinity X1.

I have configured the Helix modem in bridge mode, and my pfSense router is connected to it directly.

Since I have switched to Helix, I have the following problem : For whatever reason, if the modem loses connection, is shutted down, etc, then pfSense DHCP fails to recover. The DHCP service cannot get a public WAN address. It then shoes 0.0.0.0 or n/a.

I am able to reproduce the problem every time, by disconnecting the modem power cord and reconnect it. Here are scenarios that are failing every time :

1. Router (pfSense) stays on. Disconnect and reconnect the modem
2. Router (pfSense) stays on. Restart the modem then unplug/plug the WAN cable from the router

The following procedure is the only one that manage to get pfSense WAN back on :

1. Halt router (pfSense)
2. Shutdown the modem
3. Unplug WAN from router
4. Restart the Router and Modem
5. When the router and modem are up, plug the WAN cable in router

This is extremelly inconvenient has no one from my familly is tech-saavy enough to go through this procedure every time the internet goes down.
I need help to figure out what is going on. I'd like my router get its internet connection on its own has it did before with my older modem.

Additional details:
• My WAN interface type is set to DHCP (always been)
• No address is configured in the "Reject leases from" textbox
• My model local IP address is (assuming) 10.0.0.1 (I use it to access the model web GUI)
• When I get the problem with no WAN IP, I cannot ping the gateway

The following log entries occur when I disconnect/reconnect the cable modem :

Sep 18 12:35:44 blackgate dhclient[80634]: igb0 link state up -> down
Sep 18 12:35:45 blackgate dhclient[76211]: connection closed
Sep 18 12:35:45 blackgate dhclient[76211]: exiting.
Sep 18 12:36:11 blackgate dhcpd[21898]: reuse_lease: lease age 5177 (secs) under 25% threshold, reply with unaltered, existing lease for 192.168.1.241
Sep 18 12:38:50 blackgate dhclient[90827]: Cannot open or create pidfile: No such file or directory
Sep 18 12:38:50 blackgate dhclient[91477]: PREINIT
Sep 18 12:38:50 blackgate dhclient[90827]: DHCPREQUEST on igb0 to 255.255.255.255 port 67
Sep 18 12:38:51 blackgate dhclient[90827]: igb0 link state up -> down
Sep 18 12:38:56 blackgate dhclient[90827]: DHCPREQUEST on igb0 to 255.255.255.255 port 67
Sep 18 12:38:56 blackgate dhclient[92689]: send_packet: Network is down
Sep 18 12:38:58 blackgate dhclient[90827]: igb0 link state down -> up
Sep 18 12:38:58 blackgate dhclient[90827]: DHCPREQUEST on igb0 to 255.255.255.255 port 67
Sep 18 12:39:01 blackgate dhclient[90827]: DHCPREQUEST on igb0 to 255.255.255.255 port 67
Sep 18 12:39:02 blackgate dhcpd[21898]: reuse_lease: lease age 5347 (secs) under 25% threshold, reply with unaltered, existing lease for 192.168.1.241
Sep 18 12:39:05 blackgate dhclient[90827]: DHCPREQUEST on igb0 to 255.255.255.255 port 67
Sep 18 12:39:15 blackgate dhclient[90827]: DHCPDISCOVER on igb0 to 255.255.255.255 port 67 interval 3
Sep 18 12:39:18 blackgate dhclient[90827]: DHCPDISCOVER on igb0 to 255.255.255.255 port 67 interval 7
Sep 18 12:39:25 blackgate dhclient[90827]: DHCPDISCOVER on igb0 to 255.255.255.255 port 67 interval 9
Sep 18 12:39:34 blackgate dhclient[90827]: DHCPDISCOVER on igb0 to 255.255.255.255 port 67 interval 12

Sep 18 12:39:46 blackgate dhclient[90827]: DHCPDISCOVER on igb0 to 255.255.255.255 port 67 interval 11
Sep 18 12:39:57 blackgate dhclient[90827]: DHCPDISCOVER on igb0 to 255.255.255.255 port 67 interval 15
Sep 18 12:40:12 blackgate dhclient[90827]: DHCPDISCOVER on igb0 to 255.255.255.255 port 67 interval 4
Sep 18 12:40:16 blackgate dhclient[90827]: No DHCPOFFERS received.
Sep 18 12:40:16 blackgate dhclient[90827]: Trying recorded lease 47.77.33.59
Sep 18 12:40:16 blackgate dhclient[2556]: TIMEOUT
Sep 18 12:40:16 blackgate dhclient[2770]: Starting add_new_address()
Sep 18 12:40:16 blackgate dhclient[2999]: ifconfig igb0 inet 47.77.33.59 netmask 255.255.255.0 broadcast 255.255.255.255
Sep 18 12:40:16 blackgate dhclient[3339]: New IP Address (igb0): 47.77.33.59
Sep 18 12:40:16 blackgate dhclient[3547]: New Subnet Mask (igb0): 255.255.255.0
Sep 18 12:40:16 blackgate dhclient[3641]: New Broadcast Address (igb0): 255.255.255.255
Sep 18 12:40:16 blackgate dhclient[4089]: New Routers (igb0): 47.77.33.1
Sep 18 12:40:17 blackgate dhclient[4449]: New Routers (igb0): 47.77.33.1
Sep 18 12:40:18 blackgate dhclient[11153]: Deleting old routes
Sep 18 12:40:18 blackgate dhclient[90827]: No working leases in persistent database - sleeping.
Sep 18 12:40:18 blackgate dhclient[11944]: FAIL

Sep 18 12:41:16 blackgate dhcpd[98474]: Internet Systems Consortium DHCP Server 4.4.2-P1
Sep 18 12:41:16 blackgate dhcpd[98474]: Copyright 2004-2021 Internet Systems Consortium.
Sep 18 12:41:16 blackgate dhcpd[98474]: All rights reserved.
Sep 18 12:41:16 blackgate dhcpd[98474]: For info, please visit https://www.isc.org/software/dhcp/
Sep 18 12:41:16 blackgate dhcpd[98474]: Config file: /etc/dhcpd.conf
Sep 18 12:41:16 blackgate dhcpd[98474]: Database file: /var/db/dhcpd.leases
Sep 18 12:41:16 blackgate dhcpd[98474]: PID file: /var/run/dhcpd.pid
Sep 18 12:41:16 blackgate dhcpd[98474]: Internet Systems Consortium DHCP Server 4.4.2-P1
Sep 18 12:41:16 blackgate dhcpd[98474]: Copyright 2004-2021 Internet Systems Consortium.
Sep 18 12:41:16 blackgate dhcpd[98474]: All rights reserved.
Sep 18 12:41:16 blackgate dhcpd[98474]: For info, please visit https://www.isc.org/software/dhcp/
Sep 18 12:41:16 blackgate dhcpd[98474]: Wrote 0 class decls to leases file.
Sep 18 12:41:16 blackgate dhcpd[98474]: Wrote 0 deleted host decls to leases file.
Sep 18 12:41:16 blackgate dhcpd[98474]: Wrote 0 new dynamic host decls to leases file.
Sep 18 12:41:16 blackgate dhcpd[98474]: Wrote 55 leases to leases file.
Sep 18 12:41:16 blackgate dhcpd[98474]: Listening on BPF/igb1/00:01:c0:23:e8:f4/192.168.1.0/24
Sep 18 12:41:16 blackgate dhcpd[98474]: Sending on BPF/igb1/00:01:c0:23:e8:f4/192.168.1.0/24
Sep 18 12:41:16 blackgate dhcpd[98474]: Sending on Socket/fallback/fallback-net
Sep 18 12:41:16 blackgate dhcpd[98474]: Server starting service.
Sep 18 12:41:16 blackgate dhclient[92689]: connection closed
Sep 18 12:41:16 blackgate dhclient[92689]: exiting.
Sep 18 12:41:17 blackgate dhclient[6635]: Cannot open or create pidfile: No such file or directory
Sep 18 12:41:17 blackgate dhclient[8194]: PREINIT
Sep 18 12:41:17 blackgate dhclient[6635]: DHCPREQUEST on igb0 to 255.255.255.255 port 67
Sep 18 12:41:21 blackgate dhclient[6635]: DHCPREQUEST on igb0 to 255.255.255.255 port 67
Sep 18 12:41:31 blackgate dhclient[6635]: DHCPDISCOVER on igb0 to 255.255.255.255 port 67 interval 4
Sep 18 12:41:35 blackgate dhclient[6635]: DHCPDISCOVER on igb0 to 255.255.255.255 port 67 interval 10
Sep 18 12:41:45 blackgate dhclient[6635]: DHCPDISCOVER on igb0 to 255.255.255.255 port 67 interval 13
Sep 18 12:41:58 blackgate dhclient[6635]: DHCPDISCOVER on igb0 to 255.255.255.255 port 67 interval 9
Sep 18 12:42:07 blackgate dhclient[6635]: DHCPDISCOVER on igb0 to 255.255.255.255 port 67 interval 10
Sep 18 12:42:17 blackgate dhclient[6635]: DHCPDISCOVER on igb0 to 255.255.255.255 port 67 interval 10
Sep 18 12:42:27 blackgate dhclient[6635]: DHCPDISCOVER on igb0 to 255.255.255.255 port 67 interval 5
Sep 18 12:42:32 blackgate dhclient[6635]: No DHCPOFFERS received.
Sep 18 12:42:32 blackgate dhclient[6635]: Trying recorded lease 47.77.33.59
Sep 18 12:42:32 blackgate dhclient[95027]: TIMEOUT
Sep 18 12:42:32 blackgate dhclient[95263]: Starting add_new_address()
Sep 18 12:42:32 blackgate dhclient[95381]: ifconfig igb0 inet 47.77.33.59 netmask 255.255.255.0 broadcast 255.255.255.255
Sep 18 12:42:32 blackgate dhclient[95474]: New IP Address (igb0): 47.77.33.59
Sep 18 12:42:32 blackgate dhclient[95804]: New Subnet Mask (igb0): 255.255.255.0
Sep 18 12:42:32 blackgate dhclient[95882]: New Broadcast Address (igb0): 255.255.255.255
Sep 18 12:42:32 blackgate dhclient[96086]: New Routers (igb0): 47.77.33.1
Sep 18 12:42:33 blackgate dhclient[96687]: New Routers (igb0): 47.77.33.1
Sep 18 12:42:34 blackgate dhclient[4162]: Deleting old routes
Sep 18 12:42:34 blackgate dhclient[6635]: No working leases in persistent database - sleeping.
Sep 18 12:42:34 blackgate dhclient[5174]: FAIL

Some basic questions:

Are the DHCPREQUEST to 255.255.255.255 entries the actual WAN IP request sent to my modem? Why the .255 address?
What is the difference between DHCPDISCOVER and DHCPREQUEST ?

In another of my log files generated when the DHCP could actually get the WAN IP, I could see the following entries:

Sep 18 10:19:12 blackgate dhclient[48148]: DHCPDISCOVER on igb0 to 255.255.255.255 port 67 interval 16
Sep 18 10:19:12 blackgate dhclient[48148]: DHCPOFFER from 10.23.113.85
Sep 18 10:19:12 blackgate dhclient[66015]: ARPSEND
Sep 18 10:19:14 blackgate dhclient[70438]: ARPCHECK
Sep 18 10:19:14 blackgate dhclient[48148]: DHCPREQUEST on igb0 to 255.255.255.255 port 67
Sep 18 10:19:14 blackgate dhclient[48148]: DHCPACK from 10.23.113.85
Sep 18 10:19:14 blackgate dhclient[70825]: BOUND

I don't recognize the 10.23.113.85 address, it certainly isn't the WAN public IP. Regardless, it is followed by the following and it actually works:

Sep 18 10:19:14 blackgate dhclient[71063]: Starting add_new_address()
Sep 18 10:19:14 blackgate dhclient[71198]: ifconfig igb0 inet 47.77.33.59 netmask 255.255.255.0 broadcast 255.255.255.255
Sep 18 10:19:14 blackgate dhclient[71812]: New IP Address (igb0): 47.77.33.59
Sep 18 10:19:14 blackgate dhclient[72079]: New Subnet Mask (igb0): 255.255.255.0
Sep 18 10:19:14 blackgate dhclient[72166]: New Broadcast Address (igb0): 255.255.255.255
Sep 18 10:19:14 blackgate dhclient[72245]: New Routers (igb0): 47.77.33.1
Sep 18 10:19:14 blackgate dhclient[72261]: Adding new routes to interface: igb0
Sep 18 10:19:14 blackgate dhclient[72997]: /sbin/route add -host 47.77.33.1 -iface igb0
Sep 18 10:19:14 blackgate dhclient[73420]: /sbin/route add default 47.77.33.1
Sep 18 10:19:14 blackgate dhclient[73605]: Creating resolv.conf
Sep 18 10:19:14 blackgate dhclient[48148]: bound to 47.77.33 -- renewal in 83676 seconds.
Sep 18 10:19:20 blackgate dhcpd[65584]: Internet Systems Consortium DHCP Server 4.4.2-P1
Sep 18 10:19:20 blackgate dhcpd[65584]: Copyright 2004-2021 Internet Systems Consortium.
Sep 18 10:19:20 blackgate dhcpd[65584]: All rights reserved.

I suspect that whatever causes the routes to be deleted, when it is done, pfSense can't recover from it. It should be the reason why I cannot ping the gateway.

Other things I have tested:
• Unchecked the WAN interface blocking rules :
○ Block private networks and loopback addresses
○ Block bogon networks
• Changed the DHCP client configuration Protocol timings. I didn't had any repeatable successes with it but I must admit that I am unsure about how to figure out the right timings. My modem takes 90 seconds to reboot. I believe that if the modem reboots within the configured timeout, it works but even though I could crank that up, I would expect that whatever modem's downtime happens, the router should be able to recover gracefully from it so I don't have to worry about it.

I'm lost here.
Any help would be appreciated, thank you.

SteveITS · Sep 18, 2021, 8:47 PM

What NIC is your pfSense WAN?

Does it happen if you just unplug the cable between the pfSense and your ISP router?

Does the ISP router have multiple LAN ports, and if so does it recover if you move the patch cable to another one?

And you're saying just restarting the pfSense (preferably correctly, via the menu) doesn't recover either?

The 255.255.255.255 address is correct, see https://docs.microsoft.com/en-us/windows-server/troubleshoot/dynamic-host-configuration-protocol-basics.

JKnott · Sep 18, 2021, 8:48 PM

@jgauthier

What happens if you put a switch in between pfsense and the modem? Also, why is it failing so often. Seems to me there's a problem with the modem. Does Videotron support see the failure? They have their own logs to check. Since changing the modem was the apparent trigger, your first calls should be to them.

jgauthier · Sep 19, 2021, 4:22 PM

@jknott I don't have an additional switch to test this unfortunately.
As for the Videotron quality of service, It is actually excellent and I have no complain to do to them. As good as prior the upgrade to Helix.

I had 2 occurrences in the last month where I woke up in the morning with no internet. Both times, we've had big storms and although both the modem and router are plugged in a UPS, internet was down. I had to follow the above mentioned procedure to get internet back as pfSense had no WAN IP.

Since then, I am doing my own "failover" tests by disconnecting the modem manually and see whether the router recovers gracefully, what led to my post.

thank you

jpvonhemel · Sep 19, 2021, 6:59 PM

@jgauthier I use an xfinity xb7 with an xg-7100 and I don’t recall ever having an issue with pfsense not getting a dhcp wan ip when powered up.

jgauthier · Sep 25, 2021, 2:41 PM

@steveits sorry for the delays in responding to you. I can only mess with this early mornings in the week-ends while no one else need Internet.

The WAN NIC is an Intel I211
"Does the ISP router have multiple LAN ports, and if so does it recover if you move the patch cable to another one? " No
"And you're saying just restarting the pfSense (preferably correctly, via the menu) doesn't recover either? " No

Here are other tests I ran this morning while I was at it :

[While router and modem were working fine]
-Disconnect/reconnect WAN cable from modem: OK
-Rebooting router (modem kept on) : OK
-Switching lan port on modem while the router is up: OK

Other tests and resulting log files:

[Test1]
Protocol Timing / Timeout : Saved Cfg, 180 sec
Unplug modem AC Power
Wait 60 sec
Reconnect modem AC (takes 90 sec to be up)
Outcome: Works!

Sep 25 09:21:07 blackgate dhclient[52322]: igb0 link state up -> down
Sep 25 09:21:08 blackgate dhclient[35481]: connection closed
Sep 25 09:21:08 blackgate dhclient[35481]: exiting.
Sep 25 09:23:20 blackgate dhclient[10253]: Cannot open or create pidfile: No such file or directory
Sep 25 09:23:20 blackgate dhclient[10633]: PREINIT
Sep 25 09:23:20 blackgate dhclient[10253]: DHCPREQUEST on igb0 to 255.255.255.255 port 67
Sep 25 09:23:21 blackgate dhclient[10253]: DHCPREQUEST on igb0 to 255.255.255.255 port 67
Sep 25 09:23:23 blackgate dhclient[10253]: DHCPREQUEST on igb0 to 255.255.255.255 port 67
Sep 25 09:23:23 blackgate dhclient[10253]: igb0 link state up -> down
Sep 25 09:23:27 blackgate dhclient[10253]: DHCPREQUEST on igb0 to 255.255.255.255 port 67
Sep 25 09:23:27 blackgate dhclient[11101]: send_packet: Network is down
Sep 25 09:23:29 blackgate dhclient[10253]: igb0 link state down -> up
Sep 25 09:23:29 blackgate dhclient[10253]: DHCPREQUEST on igb0 to 255.255.255.255 port 67
Sep 25 09:23:30 blackgate dhclient[10253]: DHCPREQUEST on igb0 to 255.255.255.255 port 67
Sep 25 09:23:31 blackgate dhclient[10253]: DHCPREQUEST on igb0 to 255.255.255.255 port 67
Sep 25 09:23:33 blackgate dhclient[10253]: DHCPREQUEST on igb0 to 255.255.255.255 port 67
Sep 25 09:23:37 blackgate dhclient[10253]: DHCPREQUEST on igb0 to 255.255.255.255 port 67
Sep 25 09:23:48 blackgate dhclient[10253]: DHCPDISCOVER on igb0 to 255.255.255.255 port 67 interval 2
Sep 25 09:23:50 blackgate dhclient[10253]: DHCPDISCOVER on igb0 to 255.255.255.255 port 67 interval 3
Sep 25 09:23:53 blackgate dhclient[10253]: DHCPDISCOVER on igb0 to 255.255.255.255 port 67 interval 5
Sep 25 09:23:58 blackgate dhclient[10253]: DHCPDISCOVER on igb0 to 255.255.255.255 port 67 interval 10
Sep 25 09:24:08 blackgate dhclient[10253]: DHCPDISCOVER on igb0 to 255.255.255.255 port 67 interval 14
Sep 25 09:24:08 blackgate dhclient[10253]: DHCPOFFER from 10.23.113.85
Sep 25 09:24:08 blackgate dhclient[34430]: ARPSEND
Sep 25 09:24:10 blackgate dhclient[36707]: ARPCHECK
Sep 25 09:24:10 blackgate dhclient[10253]: DHCPREQUEST on igb0 to 255.255.255.255 port 67
Sep 25 09:24:10 blackgate dhclient[10253]: DHCPACK from 10.23.113.85
Sep 25 09:24:10 blackgate dhclient[40019]: BOUND
Sep 25 09:24:10 blackgate dhclient[40353]: Starting add_new_address()
Sep 25 09:24:10 blackgate dhclient[40844]: ifconfig igb0 inet 47.77.33.59 netmask 255.255.255.0 broadcast 255.255.255.255
Sep 25 09:24:10 blackgate dhclient[41500]: New IP Address (igb0): 47.77.33.59
Sep 25 09:24:10 blackgate dhclient[41700]: New Subnet Mask (igb0): 255.255.255.0
Sep 25 09:24:10 blackgate dhclient[41854]: New Broadcast Address (igb0): 255.255.255.255
Sep 25 09:24:10 blackgate dhclient[41890]: New Routers (igb0): 47.77.33.1
Sep 25 09:24:10 blackgate dhclient[42022]: Adding new routes to interface: igb0
Sep 25 09:24:10 blackgate dhclient[43074]: /sbin/route add -host 47.77.33.1 -iface igb0
Sep 25 09:24:10 blackgate dhclient[43490]: /sbin/route add default 47.77.33.1
Sep 25 09:24:10 blackgate dhclient[43752]: Creating resolv.conf
Sep 25 09:24:10 blackgate dhclient[10253]: bound to 47.77.33.59 -- renewal in 118866 seconds.
Sep 25 09:24:17 blackgate dhcpd[35789]: Internet Systems Consortium DHCP Server 4.4.2-P1
Sep 25 09:24:17 blackgate dhcpd[35789]: Copyright 2004-2021 Internet Systems Consortium.
Sep 25 09:24:17 blackgate dhcpd[35789]: All rights reserved.
Sep 25 09:24:17 blackgate dhcpd[35789]: For info, please visit https://www.isc.org/software/dhcp/
Sep 25 09:24:17 blackgate dhcpd[35789]: Config file: /etc/dhcpd.conf
Sep 25 09:24:17 blackgate dhcpd[35789]: Database file: /var/db/dhcpd.leases
Sep 25 09:24:17 blackgate dhcpd[35789]: PID file: /var/run/dhcpd.pid
Sep 25 09:24:17 blackgate dhcpd[35789]: Internet Systems Consortium DHCP Server 4.4.2-P1
Sep 25 09:24:17 blackgate dhcpd[35789]: Copyright 2004-2021 Internet Systems Consortium.
Sep 25 09:24:17 blackgate dhcpd[35789]: All rights reserved.
Sep 25 09:24:17 blackgate dhcpd[35789]: For info, please visit https://www.isc.org/software/dhcp/
Sep 25 09:24:17 blackgate dhcpd[35789]: Wrote 0 class decls to leases file.
Sep 25 09:24:17 blackgate dhcpd[35789]: Wrote 0 deleted host decls to leases file.
Sep 25 09:24:17 blackgate dhcpd[35789]: Wrote 0 new dynamic host decls to leases file.
Sep 25 09:24:17 blackgate dhcpd[35789]: Wrote 55 leases to leases file.
Sep 25 09:24:17 blackgate dhcpd[35789]: Listening on BPF/igb1/00:01:c0:23:e8:f4/192.168.1.0/24
Sep 25 09:24:17 blackgate dhcpd[35789]: Sending on BPF/igb1/00:01:c0:23:e8:f4/192.168.1.0/24
Sep 25 09:24:17 blackgate dhcpd[35789]: Sending on Socket/fallback/fallback-net
Sep 25 09:24:17 blackgate dhcpd[35789]: Server starting service.
Sep 25 09:24:17 blackgate dhclient[11101]: connection closed
Sep 25 09:24:17 blackgate dhclient[11101]: exiting.
Sep 25 09:24:18 blackgate dhclient[46692]: Cannot open or create pidfile: No such file or directory
Sep 25 09:24:18 blackgate dhclient[47650]: PREINIT
Sep 25 09:24:18 blackgate dhclient[46692]: DHCPREQUEST on igb0 to 255.255.255.255 port 67
Sep 25 09:24:18 blackgate dhclient[46692]: DHCPACK from 10.23.113.85
Sep 25 09:24:18 blackgate dhclient[52271]: REBOOT
Sep 25 09:24:18 blackgate dhclient[52896]: Starting add_new_address()
Sep 25 09:24:18 blackgate dhclient[53412]: ifconfig igb0 inet 47.77.33.59 netmask 255.255.255.0 broadcast 255.255.255.255
Sep 25 09:24:18 blackgate dhclient[54300]: New IP Address (igb0): 47.77.33.59
Sep 25 09:24:18 blackgate dhclient[54562]: New Subnet Mask (igb0): 255.255.255.0
Sep 25 09:24:18 blackgate dhclient[55019]: New Broadcast Address (igb0): 255.255.255.255
Sep 25 09:24:18 blackgate dhclient[55350]: New Routers (igb0): 47.77.33.1
Sep 25 09:24:18 blackgate dhclient[56158]: Adding new routes to interface: igb0
Sep 25 09:24:18 blackgate dhclient[57764]: /sbin/route add -host 47.77.33.1 -iface igb0
Sep 25 09:24:18 blackgate dhclient[58605]: /sbin/route add default 47.77.33.1
Sep 25 09:24:18 blackgate dhclient[59451]: Creating resolv.conf
Sep 25 09:24:18 blackgate dhclient[46692]: bound to 47.77.33.59 -- renewal in 118862 seconds.
Sep 25 09:24:26 blackgate dhcpd[79884]: Internet Systems Consortium DHCP Server 4.4.2-P1
Sep 25 09:24:26 blackgate dhcpd[79884]: Copyright 2004-2021 Internet Systems Consortium.
Sep 25 09:24:26 blackgate dhcpd[79884]: All rights reserved.
Sep 25 09:24:26 blackgate dhcpd[79884]: For info, please visit https://www.isc.org/software/dhcp/
Sep 25 09:24:26 blackgate dhcpd[79884]: Config file: /etc/dhcpd.conf
Sep 25 09:24:26 blackgate dhcpd[79884]: Database file: /var/db/dhcpd.leases
Sep 25 09:24:26 blackgate dhcpd[79884]: PID file: /var/run/dhcpd.pid
Sep 25 09:24:26 blackgate dhcpd[79884]: Internet Systems Consortium DHCP Server 4.4.2-P1
Sep 25 09:24:26 blackgate dhcpd[79884]: Copyright 2004-2021 Internet Systems Consortium.
Sep 25 09:24:26 blackgate dhcpd[79884]: All rights reserved.
Sep 25 09:24:26 blackgate dhcpd[79884]: For info, please visit https://www.isc.org/software/dhcp/
Sep 25 09:24:26 blackgate dhcpd[79884]: Wrote 0 class decls to leases file.
Sep 25 09:24:26 blackgate dhcpd[79884]: Wrote 0 deleted host decls to leases file.
Sep 25 09:24:26 blackgate dhcpd[79884]: Wrote 0 new dynamic host decls to leases file.
Sep 25 09:24:26 blackgate dhcpd[79884]: Wrote 55 leases to leases file.
Sep 25 09:24:26 blackgate dhcpd[79884]: Listening on BPF/igb1/00:01:c0:23:e8:f4/192.168.1.0/24
Sep 25 09:24:26 blackgate dhcpd[79884]: Sending on BPF/igb1/00:01:c0:23:e8:f4/192.168.1.0/24
Sep 25 09:24:26 blackgate dhcpd[79884]: Sending on Socket/fallback/fallback-net
Sep 25 09:24:26 blackgate dhcpd[79884]: Server starting service.

[Test 2]
Protocol Timing / Timeout : Saved Cfg, 180 sec
Unplug modem AC Power
Wait 120 sec
Reconnect modem AC (takes 90 sec to be up)
Outcome: FAILS

Sep 25 09:32:24 blackgate dhclient[64266]: igb0 link state up -> down
Sep 25 09:32:25 blackgate dhclient[49000]: connection closed
Sep 25 09:32:25 blackgate dhclient[49000]: exiting.
Sep 25 09:35:26 blackgate dhclient[15519]: Cannot open or create pidfile: No such file or directory
Sep 25 09:35:26 blackgate dhclient[16021]: PREINIT
Sep 25 09:35:26 blackgate dhclient[15519]: DHCPREQUEST on igb0 to 255.255.255.255 port 67
Sep 25 09:35:27 blackgate dhclient[15519]: DHCPREQUEST on igb0 to 255.255.255.255 port 67
Sep 25 09:35:28 blackgate dhclient[15519]: DHCPREQUEST on igb0 to 255.255.255.255 port 67
Sep 25 09:35:28 blackgate dhclient[15519]: igb0 link state up -> down
Sep 25 09:35:29 blackgate dhclient[15519]: DHCPREQUEST on igb0 to 255.255.255.255 port 67
Sep 25 09:35:29 blackgate dhclient[16842]: send_packet: Network is down
Sep 25 09:35:31 blackgate dhclient[15519]: DHCPREQUEST on igb0 to 255.255.255.255 port 67
Sep 25 09:35:31 blackgate dhclient[16842]: send_packet: Network is down
Sep 25 09:35:33 blackgate dhclient[15519]: DHCPREQUEST on igb0 to 255.255.255.255 port 67
Sep 25 09:35:33 blackgate dhclient[16842]: send_packet: Network is down
Sep 25 09:35:34 blackgate dhclient[15519]: igb0 link state down -> up
Sep 25 09:35:34 blackgate dhclient[15519]: DHCPREQUEST on igb0 to 255.255.255.255 port 67
Sep 25 09:35:35 blackgate dhclient[15519]: DHCPREQUEST on igb0 to 255.255.255.255 port 67
Sep 25 09:35:37 blackgate dhclient[15519]: DHCPREQUEST on igb0 to 255.255.255.255 port 67
Sep 25 09:35:41 blackgate dhclient[15519]: DHCPREQUEST on igb0 to 255.255.255.255 port 67
Sep 25 09:35:51 blackgate dhclient[15519]: DHCPDISCOVER on igb0 to 255.255.255.255 port 67 interval 1
Sep 25 09:35:52 blackgate dhclient[15519]: DHCPDISCOVER on igb0 to 255.255.255.255 port 67 interval 2
Sep 25 09:35:54 blackgate dhclient[15519]: DHCPDISCOVER on igb0 to 255.255.255.255 port 67 interval 4
Sep 25 09:35:58 blackgate dhclient[15519]: DHCPDISCOVER on igb0 to 255.255.255.255 port 67 interval 8
Sep 25 09:36:06 blackgate dhclient[15519]: DHCPDISCOVER on igb0 to 255.255.255.255 port 67 interval 9
Sep 25 09:36:15 blackgate dhclient[15519]: DHCPDISCOVER on igb0 to 255.255.255.255 port 67 interval 11
Sep 25 09:36:26 blackgate dhclient[15519]: DHCPDISCOVER on igb0 to 255.255.255.255 port 67 interval 18
Sep 25 09:36:44 blackgate dhclient[15519]: DHCPDISCOVER on igb0 to 255.255.255.255 port 67 interval 8
Sep 25 09:36:52 blackgate dhclient[15519]: DHCPDISCOVER on igb0 to 255.255.255.255 port 67 interval 17
Sep 25 09:37:09 blackgate dhclient[15519]: DHCPDISCOVER on igb0 to 255.255.255.255 port 67 interval 10
Sep 25 09:37:19 blackgate dhclient[15519]: DHCPDISCOVER on igb0 to 255.255.255.255 port 67 interval 11
Sep 25 09:37:30 blackgate dhclient[15519]: DHCPDISCOVER on igb0 to 255.255.255.255 port 67 interval 8
Sep 25 09:37:38 blackgate dhclient[15519]: DHCPDISCOVER on igb0 to 255.255.255.255 port 67 interval 13
Sep 25 09:37:51 blackgate dhclient[15519]: DHCPDISCOVER on igb0 to 255.255.255.255 port 67 interval 18
Sep 25 09:38:09 blackgate dhclient[15519]: DHCPDISCOVER on igb0 to 255.255.255.255 port 67 interval 10
Sep 25 09:38:19 blackgate dhclient[15519]: DHCPDISCOVER on igb0 to 255.255.255.255 port 67 interval 13
Sep 25 09:38:32 blackgate dhclient[15519]: DHCPDISCOVER on igb0 to 255.255.255.255 port 67 interval 13
Sep 25 09:38:45 blackgate dhclient[15519]: DHCPDISCOVER on igb0 to 255.255.255.255 port 67 interval 7
Sep 25 09:38:52 blackgate dhclient[15519]: No DHCPOFFERS received.
Sep 25 09:38:52 blackgate dhclient[15519]: Trying recorded lease 47.77.33.59
Sep 25 09:38:52 blackgate dhclient[14315]: TIMEOUT
Sep 25 09:38:52 blackgate dhclient[14427]: Starting add_new_address()
Sep 25 09:38:52 blackgate dhclient[14743]: ifconfig igb0 inet 47.77.33.59 netmask 255.255.255.0 broadcast 255.255.255.255
Sep 25 09:38:52 blackgate dhclient[15241]: New IP Address (igb0): 47.77.33.59
Sep 25 09:38:52 blackgate dhclient[15454]: New Subnet Mask (igb0): 255.255.255.0
Sep 25 09:38:52 blackgate dhclient[15555]: New Broadcast Address (igb0): 255.255.255.255
Sep 25 09:38:52 blackgate dhclient[15607]: New Routers (igb0): 47.77.33.1
Sep 25 09:38:53 blackgate dhclient[26735]: New Routers (igb0): 47.77.33.1
Sep 25 09:38:54 blackgate dhclient[45472]: Deleting old routes
Sep 25 09:38:54 blackgate dhclient[15519]: No working leases in persistent database - sleeping.
Sep 25 09:38:54 blackgate dhclient[46769]: FAIL

It looks like any downtime longer than the configured protocol timing's timeout setting doesn't recover. I could of course crank it up but I have no way to know in advance how long a real downtime is going to be so, its not a good solution and there must be a way..

thank you

Gertjan · Sep 27, 2021, 2:20 PM

@jgauthier

There are some DHCP-client settings that might be useful here :
These :

Check the 'Advanced Configuration' to see them.

Click on the blue "here" link for guidance.

Strange that, after a interface UP event on "09:35:34", more then 3 minutes later, on "09:38:52" there is still no answer.
The DHCP client assigns a previous used IP 47.77.33.59. It would be better if it assigned itself a NaN IP like "0.0.0.0".