Unusual Unbound Behavior

[AsgardianFW]

Earlier today, I lost my internet connection for about 5 minutes (during which time the cable modem rebooted itself).  The cable modem eventually came back online properly and pfSense didn't quite recover 100%.  There were 2 issues that seemed off:

1. The DNS Resolver could not resolve any of my local devices.  I have both "Register DHCP leases in the DNS Resolver" and "Register DHCP static mappings in the DNS Resolver" options selected.  Also, the Resolver could not resolve pfSense itself (for example, pfsense.mydomain.local failed to resolve).
2. I also have several host overrides specified (for the purpose of redirecting external domain names to internal servers on my LAN).  However, the Resolver was ignoring these and was resolving the hosts to their external IP address.

I also see several possibly relevant issues in the logs.  There are hundred of these all with the same time stamp:
Feb 8 13:04:50 unbound 18101:0 error: can't bind socket: Can't assign requested address for 192.168.100.10

I have dozens of these:
Feb 8 13:03:25 kernel arpresolve: can't allocate llinfo for 73.120.95.1 on re1

And some of these:
Feb 8 13:03:37 php-fpm 49304 /rc.linkup: The command '/sbin/dhclient -c /var/etc/dhclient_wan.conf re1 > /tmp/re1_output 2> /tmp/re1_error_output' returned exit code '1', the output was ''

Feb 8 13:04:48 php-fpm 85513 /rc.newwanip: The command '/usr/local/sbin/unbound -c /var/unbound/unbound.conf' returned exit code '1', the output was '[1454954688] unbound[25455:0] error: bind: address already in use [1454954688] unbound[25455:0] fatal error: could not open ports'

Restarting unbound seemed to clear up the issues.  I'm currently running 2.3.b.20160206.1322 and I've had cable modem reboots happen a couple of times on previous beta versions and didn't see these issues.  Maybe this is just a fluke as it looks like the cable modem issued a couple of different "internal" IP's before finally dishing out my real external IP.  Everything else seemed to be operating normally.

Please let me know if anyone would like more info from me and I'll post back if it happens again.

[LinuxTracker]

@AsgardianFW:

I have dozens of these:
Feb 8 13:03:25 kernel arpresolve: can't allocate llinfo for 73.120.95.1 on re1

As to that particular issue, a couple of us have run into it.
It's kind of a catch-all BSD warning.

I hit on a solution for my machines and posted it here.
https://forum.pfsense.org/index.php?topic=105977.msg594067#msg594067

Hopefully it'll help clear that out of your log.

[AsgardianFW]

Thanks for the tip but I don't usually have that error.  It seemed specific to this one instance when the cable modem was cycling through 2 or 3 internal IP's before landing on my actual public IP (as the error only shows up during the 5 minutes that the cable modem was trying to reconnect).  I also don't have any packages installed at the moment so it certainly isn't related to pfBlocker.  My firewall rules are quite simple at the moment and don't contain any loopback addresses.

[cmb]

He's confusing that log with the other. The "can't allocate llinfo" is normal when the default gateway you previously had is unreachable, which is normal in the circumstance you describe.

The other logs indicate unbound was trying to start while it was already running. The dhclient error on linkup is similar. I was able to replicate both of those by cycling link on a DHCP client NIC multiple times in succession, will track down the root cause from there. It's harmless log spam in this case though.