Hi Simon, thanks for taking a look at this.
I have checked again under Debian Sid with dnsmasq from the Git repo as of
2022-07-22. The tl;dr is again I have reproduced this bug with both (1)
address= and (2) host-record=. But (3) dynamic-host= continues to work
fine.
In more detail:
Everything below is exactly as tested, except for privacy I have
censored/modified my DUID and private IPv4 range (not the IPv6 range
however - I quickly created a new one for this). Also, I don't know if you
will receive this with rich formatting, but I have highlighted in orange all
bits that I've censored/modified - just in case you think there may be some
key difference I'm not showing (although I really doubt it!)
After each config change but before checking DNS, on my Windows test
machine I have performed an ipconfig /release6 and ipconfig /renew6 - to
ensure it's renewing the lease with dnsmasq.
(0) Full config used for testing:
domain=example.org
auth-zone=example.org
auth-server=example.org,
dhcp-range=fd50::1000,fd50::ffff,64,1h
dhcp-host=id:<DUID>, [fd50::10], Computer1
address=/Computer1.example.org/10.0.0.10
#host-record=Computer1.example.org,10.0.0.10
#dynamic-host=Computer1.example.org, 10.0.0.10, eth0
fd50::/64 is being advertised by a router on the network, with the Managed
Address flag set.
(1) With config as in (0); DNS only provides IPv6 address / AAAA record.
Nslookup (Windows):
> nslookup Computer1.example.org 10.0.0.1
Server: UnKnown
Address: 10.0.0.1
Name: Computer1.example.org
Address: fd50::10
Dig:
$ dig @10.0.0.1 +short Computer1.example.org A Computer1.example.org AAAA
fd50::10
(2) With config as in (0) but address commented, host-record uncommented;
DNS only provides IPv6 address / AAAA record.
Nslookup (Windows):
> nslookup Computer1.example.org 10.0.0.1
Server: UnKnown
Address: 10.0.0.1
Name: Computer1.example.org
Address: fd50::10
Dig:
$ dig @10.0.0.1 +short Computer1.example.org A Computer1.example.org AAAA
fd50::10
(3) With config as in (0) but address commented, dynamic-host uncommented;
DNS provides both IPv4 address / A record and IPv6 address / AAAA record.
Nslookup (Windows):
> nslookup Computer1.example.org 10.0.0.1
Server: UnKnown
Address: 10.0.0.1
Non-authoritative answer:
Name: Computer1.example.org
Addresses: fd50::10
10.0.0.10
Dig:
$ dig @10.0.0.1 +short Computer1.example.org A Computer1.example.org AAAA
10.0.0.10
fd50::10
Hope that's all helpful!
Kind regards,
ryt51V
On Sat, 23 Jul 2022 at 18:07, Simon Kelley <si...@thekelleys.org.uk> wrote:
> This is a bug, for sure.
>
> I can see exactly why this would happen with
>
> address=/Computer1.example.org/10.0.0.10
>
> but not with
>
> host-record=Computer1.example.org,10.0.0.10,3600
>
> Please could you recheck that you are seeing the problem with
> --host-record? If you are, I've gone down the wrong track, but if you're
> not, then the fix for this is fairly simple.
>
>
> Cheers,
>
> Simon.
>
>
> On 22/07/2022 20:37, ryt 51V wrote:
> > 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 <http://example.org>
> > #auth-zone=example.org <http://example.org>
> > #auth-server=server.example.org <http://server.example.org>,
> > dhcp-range=fd00::1000,fd00::ffff,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
> > <http://Computer1.example.org/10.0.0.10>
> > #host-record=Computer1.example.org
> > <http://Computer1.example.org>,10.0.0.10,3600
> > #dynamic-host=Computer1.example.org <http://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 AAAA records for Computer1.
> > For example, using dig:
> >
> > $ dig @10.0.0.1 <http://10.0.0.1> +short Computer1.example.org
> > <http://Computer1.example.org> A Computer1.example.org
> > <http://Computer1.example.org> AAAA
> > 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 AAAA record for the IPv6 address, and no A
> > record for the IPv4 address.
> > Again, using dig:
> >
> > $ dig @10.0.0.1 <http://10.0.0.1> +short Computer1.example.org
> > <http://Computer1.example.org> A Computer1.example.org
> > <http://Computer1.example.org> AAAA
> > 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
> >
> > _______________________________________________
> > Dnsmasq-discuss mailing list
> > Dnsmasq-discuss@lists.thekelleys.org.uk
> > https://lists.thekelleys.org.uk/cgi-bin/mailman/listinfo/dnsmasq-discuss
>
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