[Dnsmasq-discuss] Temporary failure in name resolution when IPv6 is enabled

[Amit]

On Wed, Feb 3, 2021 at 12:16 PM Geert Stappers <stappers at stappers.nl> wrote:
>
> On Wed, Feb 03, 2021 at 09:27:33AM -0800, Amit wrote:
> > On Tue, Feb 2, 2021 at 11:42 PM Geert Stappers <stappers at stappers.nl> wrote:
> > > On Wed, Feb 03, 2021 at 07:36:43AM +0100, Geert Stappers wrote:
> > > > On Tue, Feb 02, 2021 at 05:57:22PM -0800, Amit wrote:
> > > > > I have been following discussions in "[Dnsmasq-discuss] v2.83 failed to
> > > > > send packet: Network is unreachable" and was happy to hear it has been
> > > > > resolved in dnsmasq v2.84-1 in debian testing.
> > > > >
> > > > > However, this still seems to affect me and I get the error:
> > > > >
> > > > > $  ping www.google.com
> > > > > ping: www.google.com: Temporary failure in name resolution
> > > > >
> > > > >
> > > > > In other notes, I am able to get it to work if I disable ipv6. I have
> > > > > confirmed several users in our local environment see this issue as well
> > > > > with the same setup. Let me know if there is anything else you need.
> > > >
> > > > All the links of the chain are needed.
> > >
> > > At least be aware there are multi links. Example of the chain:
> > > * root DNServer
> > > * DNServer
> > > * dnsmasq
> > > * client
> > >
> >
> > Yes, that is correct. So far there has been no change to the other
> > points in the chain. To verify a downgrade to dnsmasq 2.82 was
> > attempted and the system was able to resolve queries again.
>
> Acknowledge on "2.82" does work
> And I'm somewhat lost on "the system was able again"
>
>

I'll try to provide more details:

*Working case (ipv4):*
```
$ nmcli
wlp2s0: connected to Auto swafes
        "Intel 8265 / 8275"
        wifi (iwlwifi), 14:4F:8A:F0:65:2C, hw, mtu 1500
        ip4 default
        inet4 192.168.86.39/24
        route4 0.0.0.0/0
        route4 192.168.86.0/24

DNS configuration:
        servers: 192.168.86.1
        domains: lan
        interface: wlp2s0

$ dig www.debian.org

; <<>> DiG 9.16.8-Debian <<>> www.debian.org
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 54062
;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;www.debian.org.            IN    A

;; ANSWER SECTION:
www.debian.org.        299    IN    A    149.20.4.15
www.debian.org.        299    IN    A    128.31.0.62

;; Query time: 60 msec
;; SERVER: 127.0.0.1#53(127.0.0.1)
;; WHEN: Wed Feb 03 13:59:07 PST 2021
;; MSG SIZE  rcvd: 75

Feb 03 13:59:07 amituttam dnsmasq[251434]: query[A] www.debian.org
from 127.0.0.1
Feb 03 13:59:07 amituttam dnsmasq[251434]: forwarded www.debian.org to
192.168.86.1
Feb 03 13:59:07 amituttam dnsmasq[251434]: reply www.debian.org is 149.20.4.15
Feb 03 13:59:07 amituttam dnsmasq[251434]: reply www.debian.org is 128.31.0.62
```

*Not working case (ipv6 "Automatic" config in Network Manager GUI):*
```
$ nmcli
wlp2s0: connected to Auto swafes
        "Intel 8265 / 8275"
        wifi (iwlwifi), 14:4F:8A:F0:65:2C, hw, mtu 1500
        ip4 default, ip6 default
        inet4 192.168.86.39/24
        route4 0.0.0.0/0
        route4 192.168.86.0/24
        inet6 2601:647:5b00:47c:4358:3b8d:cad2:8339/64
        inet6 fe80::9625:2191:bcd1:1ac6/64
        route6 2601:647:5b00:47c::/64
        route6 ::/0
        route6 ff00::/8
        route6 fe80::/64

DNS configuration:
        servers: 192.168.86.1
        domains: lan
        interface: wlp2s0

        servers: 2601:647:5b00:47c:8c90:25ff:fe1e:21c6
        interface: wlp2s0

$ dig www.gnome.org

; <<>> DiG 9.16.8-Debian <<>> www.gnome.org
;; global options: +cmd
;; connection timed out; no servers could be reached

log-queries enabled (journalctl -u NetworkManager.service)
Feb 03 13:31:30 amituttam dnsmasq[251434]: query[A] www.gnome.org from 127.0.0.1
Feb 03 13:31:30 amituttam dnsmasq[251434]: forwarded www.gnome.org to
192.168.86.1
Feb 03 13:31:30 amituttam dnsmasq[251434]: forwarded www.gnome.org to
2601:647:5b00:47c:8c90:25ff:fe1e:21c6
```

Some other details in the log:

```
Feb 03 12:53:00 amituttam dnsmasq[251434]: compile time options: IPv6
GNU-getopt DBus no-UBus i18n IDN2 DHCP DHCPv6 no-Lua TFTP conntrack
ipset auth cryptohash DNSSEC loop-detect inotify dumpfile
```