Hi,
I am setting up dnsmasq as a local DHCPv6 server and DNS server. (I am
keeping my existing DHCPv4 server running on a separate appliance).
I am running into an issue in the following circumstances:
- auth-zone is enabled
- For a given device, there is a dhcp-host entry with the device's DUID
for an IPv6 address.
- The device is successfully obtaining this IPv6 address.
- There is an address or host-record entry for the same device's IPv4
address.
When querying the DNS server for the hostname, only the DHCPv6 IPv6 address
is provided, not the IPv4 address from the address or host-record entry.
This is problematic as I am trying to run a dual-stack network, and so need
both IPv4 and IPv6 addresses readily resolvable. That said, I am not in
any immediate need of help as using dynamic-host instead of address or
host-record is a suitable workaround. But it would be helpful to find out
whether I am missing some nuance in the configuration, or whether this is a
bug.
In more detail: Consider the following dnsmasq configuration (private
details have of course been modified)
no-resolv
domain=example.org
#auth-zone=example.org
#auth-server=server.example.org,
dhcp-range=fd00::1000,fd00::,64,1h
dhcp-host=id:00:00:00:01:23:45:67:89:AB:CD:EF:00:00:00, [fd00::10],
Computer1
address=/Computer1.example.org/10.0.0.10
#host-record=Computer1.example.org,10.0.0.10,3600
#dynamic-host=Computer1.example.org, 10.0.0.10,eth0
And assume:
- The server running dnsmasq has IPv4 10.0.0.1
- Computer1 has IPv4 10.0.0.10 (either static, or obtained from a
separate DHCPv4 server)
- Computer1 is successfully obtaining its IPv6 lease for fd00::10 from
dnsmasq
(1) In the state above, providing Computer1 has obtained its IPv6 lease
from dnsmasq, dnsmasq will provide both A and records for Computer1.
For example, using dig:
$ dig @10.0.0.1 +short Computer1.example.org A Computer1.example.org
10.0.0.10
fd00::10
>From my perspective this is expected behaviour.
(2) Now if you uncomment the auth-zone and auth-server lines, a DNS query
will *only* provide an record for the IPv6 address, and no A record
for the IPv4 address.
Again, using dig:
$ dig @10.0.0.1 +short Computer1.example.org A Computer1.example.org
fd00::10
>From my perspective this is unexpected behaviour. The address line with
the IPv4 address is for the authoritative domain, so I am unsure why it
would not be included.
(3) If you comment out the address line and uncomment the host-record line,
then DNS provides the same result as (2).
Again, this is unexpected behaviour. The host-record line is for the
authoritative domain.
(4) If you comment out the host-record line and uncomment the dynamic-host
line, then DNS provides the same result as (1).
This is expected behaviour and a suitable workaround to case (2)/(3).
Although it is odd that it's inconsistent with address and host-record
behaviour.
(5) I have also noticed that instead of using dig, one uses a Windows
nslookup, Windows will declare the response as non-authoritative for case
(4), but won't for case (2)/(3). Additionally if you remove the dhcp-range
and dhcp-host entries, nslookup will receive the IPv4 address but again it
will be marked as non-authoritative.
>From my perspective, the behaviour in (2)/(3) is not correct (nor (5),
though I don't think that will really affect me that much). The
address/host-record entries are for the domain listed in auth-zone, and so
should be included as authoritative records.
Indeed the dnsmasq man page more explicitly suggests that (3) is incorrect
behaviour for host-record entries. It says that the authoritative zone is
populated with "IPv4 and IPv6 addresses from /etc/hosts (and --addn-hosts )
and --host-record and --interface-name and ---dynamic-host provided the
address falls into one of the subnets specified in the --auth-zone."
(Explicitly adding a subnet to the auth-zone line makes no difference to
the above tests)
I have tested this with the same results with the following OS and dnsmasq
versions:
- Raspberry Pi OS Bullseye - dnsmasq 2.85-1 from RPi OS Repo
- Debian Bullseye - dnsmasq 2.85-1 from Debian Repo
- Debian Sid - dnsmasq 2.86-1.1 from Debian Repo
- Debain Sid - Latest dnsmasq from the Git repo as of 2022-07-22
Any help appreciated!
Kind regards,
ryt51v
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