DNS/DHCP stop working suddenly

stephenw10

Yup no problem there. Hmm, hard to say then without any logs to check from the time. It really looks like a disk issue though from those symptoms.

michmoor

@stephenw10
It's possible. Seeing how all logs get pumped to my syslog collector is there something i should search for?
Its also possible that because im missing .bz2 logs as i showed above they probably didnt make it to syslog.

michmoor

@stephenw10
There was also something i noticed. So to recover i did a hard reboot. Unplug and plug.
I didnt do any checkouts because all my alerts cleared but later on in the evening the wife couldnt connect to captive portal which is weird because there is no captive portal enabled on that interface.
-- if you recall i had a CP issue about a week ago and i was tshooting :)

So it seems that pfsense loaded a previous config and not the latest config. It was simple to load the recent config from back up and restore but why did an old config load?

stephenw10

It will revert to the last good config if the current config file is unreadable. That could also indicate a drive issue.

michmoor

@stephenw10 OK now im nervous.
What are my options to either replace the 6100 or replace the SSD?

stephenw10

This is the first time you've seen this issue? It might not be the disk, I would want to see something conclusive. If it is you could just replace the disk though.

michmoor

@stephenw10
It happened again..
Got some more data that may or may not help.

Internet suddenly goes out so i go straight into console.
Nothing on the console screen. Usual output for selecting options.

WAN port loses IP address

Mar  1 15:22:59 GAFW dhclient[38626]: No working leases in persistent database - sleeping.
Mar  1 15:22:59 GAFW dhclient[30526]: FAIL
Mar  1 15:23:00 GAFW dhclient[38626]: connection closed
Mar  1 15:23:00 GAFW dhclient[38626]: exiting.
Mar  1 15:23:01 GAFW dhclient[41673]: PREINIT
Mar  1 15:23:01 GAFW dhclient[43008]: EXPIRE
Mar  1 15:23:01 GAFW dhclient[44238]: Deleting old routes
Mar  1 15:23:01 GAFW dhclient[45556]: PREINIT
Mar  1 15:23:01 GAFW dhclient[41096]: DHCPDISCOVER on ix3 to 255.255.255.255 port 67 interval 2
Mar  1 15:23:03 GAFW dhclient[41096]: DHCPDISCOVER on ix3 to 255.255.255.255 port 67 interval 5
Mar  1 15:23:08 GAFW dhclient[41096]: DHCPDISCOVER on ix3 to 255.255.255.255 port 67 interval 7

CPU usage using top -aSH command.

last pid: 16707;  load averages:  4.63,  3.67,  2.21                                                                                                         up 0+15:43:45  15:11:13
519 threads:   9 running, 472 sleeping, 38 waiting
CPU:  2.0% user,  0.0% nice, 26.4% system,  0.0% interrupt, 71.7% idle
Mem: 398M Active, 1576M Inact, 1347M Wired, 4465M Free
ARC: 319M Total, 119M MFU, 187M MRU, 875K Anon, 2154K Header, 10M Other
     261M Compressed, 759M Uncompressed, 2.91:1 Ratio
Swap: 1024M Total, 1024M Free

  PID USERNAME    PRI NICE   SIZE    RES STATE    C   TIME    WCPU COMMAND
    0 root        -60    -     0B  2128K CPU3     3  13:49  99.92% [kernel{if_io_tqg_3}]
   11 root        187 ki31     0B    64K RUN      2 872:54  95.83% [idle{idle: cpu2}]
   11 root        187 ki31     0B    64K CPU1     1 867:56  95.08% [idle{idle: cpu1}]
   11 root        187 ki31     0B    64K CPU0     0 878:02  93.18% [idle{idle: cpu0}]
60326 root         68    0   114M    51M accept   1   0:02   8.47% php-fpm: pool nginx (php-fpm)
81924 www          20    0    43M    23M kqread   1  12:44   1.15% /usr/local/sbin/haproxy -f /var/etc/haproxy/haproxy.cfg -p /var/run/haproxy.pid -D -x /tmp/haproxy.socket -sf 465
20240 unbound      20    0   192M   144M kqread   0   0:01   0.60% /usr/local/sbin/unbound -c /var/unbound/unbound.conf{unbound}
42858 root         20    0    13M  3084K select   2   4:35   0.57% /usr/sbin/syslogd -O rfc3164 -s -c -c -l /var/dhcpd/var/run/log -l /tmp/haproxy_chroot/var/run/log -P /var/run/sy
20240 unbound      20    0   192M   144M kqread   1   0:01   0.53% /usr/local/sbin/unbound -c /var/unbound/unbound.conf{unbound}
63614 root         20    0  1196M   733M uwait    1   4:34   0.48% /usr/local/bin/suricata --netmap -D -c /usr/local/etc/suricata/suricata_12791_igc1/suricata.yaml --pidfile /var/r
    0 root        -64    -     0B  2128K -        1   1:21   0.28% [kernel{dummynet}]
    0 root        -12    -     0B  2128K -        1   0:41   0.23% [kernel{z_wr_iss_0}]
48900 root         20    0    13M  3520K bpf      2   2:43   0.22% /usr/local/sbin/filterlog -i pflog0 -p /var/run/filterlog.pid
    0 root        -12    -     0B  2128K -        1   0:41   0.21% [kernel{z_wr_iss_1}]

michmoor

@stephenw10

What is also strange is that i could not resolve anything local. My own self hosted services would time out..

C:\Users\michm>nslookup syslog.xxxxxxx
Server:  GAFW.xxxxxxx
Address:  192.168.50.254

DNS request timed out.
    timeout was 2 seconds.
DNS request timed out.
    timeout was 2 seconds.
*** Request to GAFW.xxxxxxxxx timed-out

I went ahead and went for the reboot through console. It could not stop the Tailscale package. This forced me to pull the plug and plug it back in.

Netgate pfSense Plus will reboot. This may take a few minutes, depending on your hardware.
Do you want to proceed?

    Y/y: Reboot normally
    R/r: Reroot (Stop processes, remount disks, re-run startup sequence)
    S: Reboot into Single User Mode (requires console access!)
    Enter: Abort

Enter an option: r

Netgate pfSense Plus is rerooting now.
 Stopping package arpwatch...done.
 Stopping package freeradius3...done.
 Stopping package lldpd...done.
 Stopping package WireGuard...done.
 Stopping package haproxy...done.
 Stopping package nut...done.
 Stopping package syslog-ng...done.
 Stopping package Tailscale...   <----- stuck here and could not go past

I eventually lost access to the web configurator and got the nginx timed out message.

stephenw10

OK interesting. Not the SSD then, so that's good.

One CPU core seems to be stuck at 100%. We can only see it's interface io traffic so something attempting (and seemingly failing) to send or receive. From the fact tailscale could not be stopped I'd guess it's that somehow. Are you able to disable that as a test?

michmoor

@stephenw10
I have uninstalled Tailscale.
I’m glad I got some more data on this so thanks for the assistance.

If this is a bug - let’s say it might be for sake of conversation - I don’t have much data to prove this isn’t just environmental to my setup. Any other data points I can gather?
Losing a WAN ip address does make Tailscale chatty but i can’t find the link to why dns breaks for local resolution.

stephenw10

It looks like whatever is using that CPU core is preventing anything sending/receiving traffic or possible opening states. Causing problem for numerous services.

michmoor

@stephenw10
Interesting and i love that theory. Seems very logical.
Would explain why almost all functionality related to the firewall is broken - web-configurator , dns , dhcp...
Considering the 6100 has 4x cores, its not odd that a single core choking the firewall breaks connectivity?

edit: So whatever is using that core is related to traffic? High throughput? This 6100 can for sure push well over 10G from my testing but looking at the monitoring i see pretty low WAN throughput considering.
Tailscale seems like the smoking gun but checking my historical syslog it seems that once ix3 (WAN) goes down and cant renew a dhcp address, tailscale becomes very verbose. As i discovered today i am unable to reboot the router because it gets stuck on the tailscale process. High level but the trigger is losing the WAN.
If we're stable this weekend, i will install tailscale again and unplug the wan..see if i can reproduce.

stephenw10

@michmoor said in DNS/DHCP stop working suddenly:

Considering the 6100 has 4x cores, its not odd that a single core choking the firewall breaks connectivity?

It is I agree. Though I'm assuming it's choking something in the network stack so it doesn't matter than then other cores are still available.

cyberconsultants

@michmoor said in DNS/DHCP stop working suddenly:

I went ahead and went for the reboot through console. It could not stop the Tailscale package. This forced me to pull the plug and plug it back in.

what's the longest you waited for the system to shutdown gracefully when it appeared to be 'stuck" stopping Tailscale package? conservative estimate in minutes...

michmoor

@cyberconsultants
maybe 5mins or so.
Reboots generally do not take long

@stephenw10 so far since the TS package removal things have been stable since. I’ll add the package tomorrow and let you know how things go.

cyberconsultants

@michmoor five minutes doesn't seem reasonable given documented precaution:

https://docs.netgate.com/pfsense/en/latest/diagnostics/system-halt.html

...and what you seemed to be dealing with more specifically.

abrupt and repeated power losses over time might be closer in line with your 'root cause' than any particular package. i personally think it'd be advisable to make not cutting the power until you've waited at least an unreasonable period of time given the specific reboot context (sysem updates, maintenance, system crash, etc.) a more regular practice.

pfSense is a software firewall that doesn't load its config strictly out of NVRAM like typical consumer devices often do. despite filesystem and backup/recovery/snapshot improvements over time, OS corruption is still a real concern with abrupt loss of system power.

stephenw10

In reality I don't think I've ever seen a correctly functioning install take more than 5 mins to shutdown.

cyberconsultants

@stephenw10 said in DNS/DHCP stop working suddenly:

In reality I don't think I've ever seen a correctly functioning install take more than 5 mins to shutdown.

so you would pull the physical power after five minutes of Stopping package Tailscale... in some kind of unstable system state?

stephenw10

If the console was hung at that point then yes. I might try hitting ctl+t first to see what it's actually waiting for. That won't allow it to continue but might give a clue as to why it failed.

cyberconsultants

@stephenw10 said in DNS/DHCP stop working suddenly:

If the console was hung at that point then yes. I might try hitting ctl+t first to see what it's actually waiting for. That won't allow it to continue but might give a clue as to why it failed.

lol