[Kea-users] DHCPv6 flooding by Windows 11 24H2 clients

[rme at bluemail.ch]

Hi Darren,

Thank you so much for your response.

It's always good to think outside the box. I am having issues with v6 
but the linked v4 documentation is also applicable for v6. Disabling 
DDNS update on renew helps taking the load from the DNS server.

However enabling lease-caching just changes the output of the 
log-flooding lines slightly. It might take off some load from the DHCP 
server though.

Not sure if I am the only one who ever noticed this issue with Windows 
11 24H2 yet or if I am the only one facing it. But it's reproducible for 
me on multiple different networks and always Windows 11 24H2 causing 
this issue. No matter if it's a PC, Laptop, upgraded or freshly installed.


Logs I am getting now:

Jan 24 22:58:09 master kea-dhcp6[17139]: INFO 
[kea-dhcp6.leases.140017378789056] DHCP6_LEASE_REUSE 
duid=[00:01:00:01:2e:a1:6e:10:d0:ad:08:30:3f:97], tid=0x6f6749: lease 
for address fddb:9f42:7afb:1::27 and iaid=181447944 has been reused for 
2591983 seconds
Jan 24 22:58:10 master kea-dhcp6[17139]: INFO 
[kea-dhcp6.leases.140017336846016] DHCP6_LEASE_REUSE 
duid=[00:01:00:01:2e:a1:6e:10:d0:ad:08:30:3f:97], tid=0x53abc8: lease 
for address fddb:9f42:7afb:1::27 and iaid=181447944 has been reused for 
2591982 seconds
Jan 24 22:58:10 master kea-dhcp6[17139]: INFO 
[kea-dhcp6.leases.140017315874496] DHCP6_LEASE_REUSE 
duid=[00:01:00:01:2e:a1:6e:10:d0:ad:08:30:3f:97], tid=0x88d499: lease 
for address fddb:9f42:7afb:1::27 and iaid=181447944 has been reused for 
2591982 seconds
Jan 24 22:58:11 master kea-dhcp6[17139]: INFO 
[kea-dhcp6.leases.140017273931456] DHCP6_LEASE_REUSE 
duid=[00:01:00:01:2e:a1:6e:10:d0:ad:08:30:3f:97], tid=0x11ee76: lease 
for address fddb:9f42:7afb:1::27 and iaid=181447944 has been reused for 
2591981 seconds
Jan 24 22:58:11 master kea-dhcp6[17139]: INFO 
[kea-dhcp6.leases.140017252959936] DHCP6_LEASE_REUSE 
duid=[00:01:00:01:2e:a1:6e:10:d0:ad:08:30:3f:97], tid=0x5bfe23: lease 
for address fddb:9f42:7afb:1::27 and iaid=181447944 has been reused for 
2591981 seconds
Jan 24 22:58:12 master kea-dhcp6[17139]: INFO 
[kea-dhcp6.leases.140017221502656] DHCP6_LEASE_REUSE 
duid=[00:01:00:01:2e:a1:6e:10:d0:ad:08:30:3f:97], tid=0x57836e: lease 
for address fddb:9f42:7afb:1::27 and iaid=181447944 has been reused for 
2591980 seconds
Jan 24 22:58:12 master kea-dhcp6[17139]: INFO 
[kea-dhcp6.leases.140017190045376] DHCP6_LEASE_REUSE 
duid=[00:01:00:01:2e:a1:6e:10:d0:ad:08:30:3f:97], tid=0xef19dd: lease 
for address fddb:9f42:7afb:1::27 and iaid=181447944 has been reused for 
2591980 seconds
Jan 24 22:58:13 master kea-dhcp6[17139]: INFO 
[kea-dhcp6.leases.140017504618176] DHCP6_LEASE_REUSE 
duid=[00:01:00:01:2e:a1:6e:10:d0:ad:08:30:3f:97], tid=0x43eeb5: lease 
for address fddb:9f42:7afb:1::27 and iaid=181447944 has been reused for 
2591979 seconds
Jan 24 22:58:13 master kea-dhcp6[17139]: INFO 
[kea-dhcp6.leases.140017431217856] DHCP6_LEASE_REUSE 
duid=[00:01:00:01:2e:a1:6e:10:d0:ad:08:30:3f:97], tid=0xac849a: lease 
for address fddb:9f42:7afb:1::27 and iaid=181447944 has been reused for 
2591979 seconds
Jan 24 22:58:14 master kea-dhcp6[17139]: INFO 
[kea-dhcp6.leases.140017399760576] DHCP6_LEASE_REUSE 
duid=[00:01:00:01:2e:a1:6e:10:d0:ad:08:30:3f:97], tid=0xc64e3e: lease 
for address fddb:9f42:7afb:1::27 and iaid=181447944 has been reused for 
2591978 seconds
Jan 24 22:58:14 master kea-dhcp6[17139]: INFO 
[kea-dhcp6.leases.140017410246336] DHCP6_LEASE_REUSE 
duid=[00:01:00:01:2e:a1:6e:10:d0:ad:08:30:3f:97], tid=0x2326ec: lease 
for address fddb:9f42:7afb:1::27 and iaid=181447944 has been reused for 
2591978 seconds
Jan 24 22:58:15 master kea-dhcp6[17139]: INFO 
[kea-dhcp6.leases.140017378789056] DHCP6_LEASE_REUSE 
duid=[00:01:00:01:2e:a1:6e:10:d0:ad:08:30:3f:97], tid=0x5f5ed7: lease 
for address fddb:9f42:7afb:1::27 and iaid=181447944 has been reused for 
2591977 seconds
Jan 24 22:58:15 master kea-dhcp6[17139]: INFO 
[kea-dhcp6.leases.140017336846016] DHCP6_LEASE_REUSE 
duid=[00:01:00:01:2e:a1:6e:10:d0:ad:08:30:3f:97], tid=0xff349: lease for 
address fddb:9f42:7afb:1::27 and iaid=181447944 has been reused for 
2591977 seconds
Jan 24 22:58:16 master kea-dhcp6[17139]: INFO 
[kea-dhcp6.leases.140017315874496] DHCP6_LEASE_REUSE 
duid=[00:01:00:01:2e:a1:6e:10:d0:ad:08:30:3f:97], tid=0xff3db1: lease 
for address fddb:9f42:7afb:1::27 and iaid=181447944 has been reused for 
2591976 seconds
Jan 24 22:58:16 master kea-dhcp6[17139]: INFO 
[kea-dhcp6.leases.140017263445696] DHCP6_LEASE_REUSE 
duid=[00:01:00:01:2e:a1:6e:10:d0:ad:08:30:3f:97], tid=0x80f84d: lease 
for address fddb:9f42:7afb:1::27 and iaid=181447944 has been reused for 
2591976 seconds
Jan 24 22:58:17 master kea-dhcp6[17139]: INFO 
[kea-dhcp6.leases.140017231988416] DHCP6_LEASE_REUSE 
duid=[00:01:00:01:2e:a1:6e:10:d0:ad:08:30:3f:97], tid=0xf63728: lease 
for address fddb:9f42:7afb:1::27 and iaid=181447944 has been reused for 
2591975 seconds
Jan 24 22:58:18 master kea-dhcp6[17139]: INFO 
[kea-dhcp6.leases.140017200531136] DHCP6_LEASE_REUSE 
duid=[00:01:00:01:2e:a1:6e:10:d0:ad:08:30:3f:97], tid=0x9c1f5f: lease 
for address fddb:9f42:7afb:1::27 and iaid=181447944 has been reused for 
2591974 seconds
Jan 24 22:58:18 master kea-dhcp6[17139]: INFO 
[kea-dhcp6.leases.140017494132416] DHCP6_LEASE_REUSE 
duid=[00:01:00:01:2e:a1:6e:10:d0:ad:08:30:3f:97], tid=0xf5e796: lease 
for address fddb:9f42:7afb:1::27 and iaid=181447944 has been reused for 
2591974 seconds
...

Thanks again for your assistance.
I am going to apply cache and disable ddns-update-on-renew everywhere 
until it's solved.

best regards,
Rainer