DHCPv6 static IPv6s not dished out

[chris42]

I am setting up a DHCP6 + SLAAC LAN network
- I am receiving a /56 prefix from my provider
- My LAN is configured within IPv6  to track interface with manual adjustments
- I left the RA settings alone
- DHCPv6 is configured to dish out IPv6 in a range from ::2:0:0:10 to ::2:0:0:0:ffff
- DHCPv6 is configured to dish out one static IPv6 (::2:0:0:9) identified by DUID

This setup seems to partially work as IPv6 via DHCP and routing information via RA is send out to the clients. However the static IPv6 is not correctly sorted. The system with the DUID requesting an IPv6 is getting one out of the dynamic pool. (I tried to manually set the static lease and use the +)

Does anyone got the static lease working or knows how to debug it?

BTW: I am using OPNsense 19.7.4_1 (amd64, LibreSSL)

[marjohn56]

If you are sure that your dhcp6 settings are correct then what are your RA settings under services?


There are several options, if set to managed then only the dhcp6 server will give out addresses, but that will screw up any android devices. Set it to assisted and that should give you the best of both worlds.

[chris42]

I do not have a reference, so I can't tell if the settings are correct. However the DHCPv6 itself works, as my client gets an address out of the pool.
The issue is, that I do not get the static address I defined, but just a random one out of the pool. Hence somewhere the identification of the client seems to go wrong?

P.S.: Within the RA, I set assissted, which works fine with Android

[marjohn56]

What type of device is the client, or are there multiple clients all showing the same issue?

[chris42]

I only tested the static lease with one client so far, a Debian Buster Linux machine. I tried to manually define the static lease and use the + symbol.

[marjohn56]

I know it was working fine on my windows mail server but that's now shut down. I'll fire up a debian VM and test.

[marjohn56]

Just checked it using my QNAP Linux station, created a new Ubuntu 16.04 instance. It got an address from Opnsense which I then added to the static assignments. I incremented the address by 1 ( so its a new address ) when I copied the given address to the address required when you add the static, filled in the rest and saved. I then rebooted the Ubuntu instance and it was given the address I had set, so it certainly works.

[chris42]

Hmm... not sure about the certainly. ;-)
Found someone in the German Forum, that has similar troubles: https://forum.opnsense.org/index.php?topic=14358.new

I will try the setup again next week. Experienced already differences between Ubuntu and Debian in handling the DHCPv6 setups (e.g. Debian seems to ignore the RA as soon as it is on the DHCPv6). Then I can use my laptop to check if it works with Ubuntu.

Thank you for testing! Infos and experience are quite sparse in IPv6, so happy to see a working setup.