Local clients' AAAA records with track6 and dnsmasq

[sbellon]

Hi all,

when using track6 on the LAN interfaces, can something be configured that local clients' IPv6 addresses are registered as AAAA records when using dnsmasq?

TIA.

Greetings,
Stefan

[sbellon]

Or is that not possible at all?

[sbellon]

Wow, this is strange ...

I just noticed that name resolution of local host names in my LAN works for A records but not for AAAA records.

I thought, let's go to OPNsense forums and search ... then I found this topic and ... :-o

Two things:

1) I completely forgot I had asked this seven months ago already.

2) I'm also puzzled as to why this got no response. Am I the only one with that issue or is my expectation stupid?

[franco]

It only works for static mappings. isc-dhcp does not offer host names in IPv6. In dynamic environments use empty prefix addresses as such ::1, etc and they will be expanded automatically.


Cheers,
Franco

[sbellon]

I'm sorry, I do not understand what you mean with "use empty prefix addresses such as ::1" ... where?

I have configured DHCPv4 for interface LAN, configured an IP range and also defined some static mappings. For the dynamic ones as well as the static ones I can properly get name resolution for A records.

If possible, I'd like to get the same for AAAA records, but I am unsure of a) whether that works at all (from your "isc-dhcp does not offer host names in IPv6" it sounds like it doesn't) or b) how to configure it.

[franco]

Again, host names are not registered in IPv6. We don't get the information in the DHCP server lease file.

# grep hostname /var/dhcpd/var/db/dhcpd.leases | wc -l
      12

vs.

# grep hostname /var/dhcpd/var/db/dhcpd6.leases | wc -l
       0

It's a small deployment, but it does have IPv6 devices.

In order to be able to use host names for IPv6 addresses it requires static mappings, go to e.g. "Services: DHCPv6: [LAN]" and at the bottom of the page there is a "DHCPv6 Static Mappings for this interface." table. There you can enter a hostname, DUID (MAC equivalent) and address. If you have a tracking interface in the manual mode where DHCPv6 configuration is permitted these addresses will merge the prefix of your interface (/64) with the suffix address you give. Prefix abcd::/64 and address ::1 will be merged as abcd::1.


Cheers,
Franco

[sbellon]

I appreciate your help very much (and of course also the work you put into OPNsense)!

Ok, I understood the fact that I need static mappings for IPv6 in order to get name resolution. That's fine with me.

However, I do not have "Services: DHCPv6: [LAN]", I only have "Relay" and "Leases" there. BTW: Relay is not enabled because I wouldn't know where to relay to.

I'm sure that I'm still missing something (small) ...

[sbellon]

Ah, I need to enable "Allow manual adjustement of DHCPv6 and Router Advertisements", then enable "Services: DHCPv6: [LAN]" and configure it.

[franco]

Yes. If the interface doesn't have a static address manual mode is required and set from the interface settings itself which will disable the automatic configuration of radvd/dhcpv6.


Cheers,
Franco

[sbellon]

Thanks for your help.

To summarize (for others, searching for similar keywords and finding this topic in the future):

- Interfaces -> [LAN] -> Track IPv6 Interface -> [v] Allow manual adjustments of DHCPv6 and Router Advertisements
- Services -> DHCPv6 -> [LAN] -> Enable (and define Lease range)
- Services -> Router Advertisements -> [LAN] -> Assisted

Then setting static IPv6 mappings via Services -> DHCPv6 -> [LAN] (or Leases) are reflected in /var/etc/dnsmasq-hosts and thus IPv4 and (those) IPv6 addresses can be resolved when using OPNsense as name server.