Kea DHCP stopped handing out IPs

Networking & Firewalls
1

Not sure what caused it, but randomly one afternoon, my pfSense decided to stop assigning IP addresses to computers joining the network. The TVs were still online, as were my servers, but phones, and PCs which were trying to access the WiFi got no love. Had been working fine for 1/2 a year, but I found this in the DHCP logs.

Aug 31 13:45:49 kea-dhcp4 56784 WARN [kea-dhcp4.alloc-engine.0x27dbcc816600] ALLOC_ENGINE_V4_ALLOC_FAIL_CLASSES [hwtype=1 34:cf:f6:2b:7c:3a], cid=[01:34:cf:f6:2b:7c:3a], tid=0x3cbc5590: Failed to allocate an IPv4 address for client with classes: ALL, VENDOR_CLASS_MSFT 5.0, pool_lan_0, UNKNOWN
Aug 31 13:45:49 kea-dhcp4 56784 WARN [kea-dhcp4.alloc-engine.0x27dbcc816600] ALLOC_ENGINE_V4_ALLOC_FAIL [hwtype=1 34:cf:f6:2b:7c:3a], cid=[01:34:cf:f6:2b:7c:3a], tid=0x3cbc5590: failed to allocate an IPv4 address after 45 attempt(s)
Aug 31 13:45:49 kea-dhcp4 56784 WARN [kea-dhcp4.alloc-engine.0x27dbcc816600] ALLOC_ENGINE_V4_ALLOC_FAIL_SUBNET [hwtype=1 34:cf:f6:2b:7c:3a], cid=[01:34:cf:f6:2b:7c:3a], tid=0x3cbc5590: failed to allocate an IPv4 lease in the subnet 192.168.1.0/24, subnet-id 1, shared network (none)
Aug 31 13:45:34 kea-dhcp4 56784 WARN [kea-dhcp4.alloc-engine.0x27dbcc816600] ALLOC_ENGINE_V4_ALLOC_FAIL_CLASSES [hwtype=1 34:cf:f6:2b:7c:3a], cid=[01:34:cf:f6:2b:7c:3a], tid=0x3cbc5590: Failed to allocate an IPv4 address for client with classes: ALL, VENDOR_CLASS_MSFT 5.0, pool_lan_0, UNKNOWN
Aug 31 13:45:34 kea-dhcp4 56784 WARN [kea-dhcp4.alloc-engine.0x27dbcc816600] ALLOC_ENGINE_V4_ALLOC_FAIL [hwtype=1 34:cf:f6:2b:7c:3a], cid=[01:34:cf:f6:2b:7c:3a], tid=0x3cbc5590: failed to allocate an IPv4 address after 45 attempt(s)
Aug 31 13:45:34 kea-dhcp4 56784 WARN [kea-dhcp4.alloc-engine.0x27dbcc816600] ALLOC_ENGINE_V4_ALLOC_FAIL_SUBNET [hwtype=1 34:cf:f6:2b:7c:3a], cid=[01:34:cf:f6:2b:7c:3a], tid=0x3cbc5590: failed to allocate an IPv4 lease in the subnet 192.168.1.0/24, subnet-id 1, shared network (none)
Aug 31 13:45:25 kea-dhcp4 56784 WARN [kea-dhcp4.alloc-engine.0x27dbcc816600] ALLOC_ENGINE_V4_ALLOC_FAIL_CLASSES [hwtype=1 34:cf:f6:2b:7c:3a], cid=[01:34:cf:f6:2b:7c:3a], tid=0x3cbc5590: Failed to allocate an IPv4 address for client with classes: ALL, VENDOR_CLASS_MSFT 5.0, pool_lan_0, UNKNOWN
Aug 31 13:45:25 kea-dhcp4 56784 WARN [kea-dhcp4.alloc-engine.0x27dbcc816600] ALLOC_ENGINE_V4_ALLOC_FAIL [hwtype=1 34:cf:f6:2b:7c:3a], cid=[01:34:cf:f6:2b:7c:3a], tid=0x3cbc5590: failed to allocate an IPv4 address after 45 attempt(s)

I had seen

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image1161Ă—137 11.5 KB

in the Advanced Options, and thinking EOL = bad, and it seemed like sooner or later I needed to use Kea, I just switched to Kea months ago. Worked fine until today, power cycles, updates, nothing helped my network until I ticked back to ISC DHCP.

Actually reading about the two versions of DHCP, sounds like while Kea is the new cool standard, many are staying with ISC, because it ain’t broke. Just a curious battle I came home to one evening.

1 Like
2

What version of pfsense are you using?

3

I was on 2.7.2-RELEASE, and performed an update to 2.8.0-RELEASE, the update didn’t resolve anything, still had a DHCP server which wasn’t handing out IPs. Switching to ISC seemed to be the isolated variable that I changed which brought my network back to life.

4

I would for sure do some testing after the upgrade. I’ve been running pfsense for years and haven’t had an issue with DHCP. The first 5 years were under the “free” version but I’ve been paying for equally as long now, if not longer.

5

Hey! Thanks for posting this. Ran into the same issue this morning and switching from kea to isc fixed it for me as well.