Are we clear that this is a dnsmasq problem, and not a systemd-resolved
one? Can you add --log-queries to the dnsmasq configuration and see what
dnsmasq is doing? That should demonstrate if the loop is dnsmasq
forwarding to itself, of if the problem is something else.


Cheers,

Simon.




On 13/03/17 08:46, Paul wrote:
> There aren't any such entries in syslog, presumably because I had
> hardcoded two upstream servers (208.67.222.222 and 208.67.220.220) using
> the GUI Wi-Fi settings dialog in 16.10 and they're not changing. Oddly,
> I can't see that setting in the 17.04 dialog, even though "systemd-
> resolve --status" correctly reports them:
> 
> Global
>          DNS Servers: 127.0.0.1
>           DNSSEC NTA: 10.in-addr.arpa
>                       16.172.in-addr.arpa
>                       168.192.in-addr.arpa
>                       17.172.in-addr.arpa
>                       18.172.in-addr.arpa
>                       19.172.in-addr.arpa
>                       20.172.in-addr.arpa
>                       21.172.in-addr.arpa
>                       22.172.in-addr.arpa
>                       23.172.in-addr.arpa
>                       24.172.in-addr.arpa
>                       25.172.in-addr.arpa
>                       26.172.in-addr.arpa
>                       27.172.in-addr.arpa
>                       28.172.in-addr.arpa
>                       29.172.in-addr.arpa
>                       30.172.in-addr.arpa
>                       31.172.in-addr.arpa
>                       corp
>                       d.f.ip6.arpa
>                       home
>                       internal
>                       intranet
>                       lan
>                       local
>                       private
>                       test
> 
> Link 2 (wlp2s0)
>       Current Scopes: DNS LLMNR/IPv4 LLMNR/IPv6
>        LLMNR setting: yes
> MulticastDNS setting: no
>       DNSSEC setting: allow-downgrade
>     DNSSEC supported: no
>          DNS Servers: 208.67.222.222
>                       208.67.220.220
>           DNS Domain: local
> 
> The requests against the upstream server are disturbingly fast, I'm
> surprised I haven't been blacklisted yet.
> 
> 19:40:12.000415 IP hostname.50776 > resolver1.opendns.com.domain: 42051+% [1au] PTR? 4.1.168.192.in-addr.arpa. (53)
> E..Q..@.@........C...X.5.=nB.C...........4.1.168.192.in-addr.arpa.......)........
> 19:40:12.000920 IP hostname.59219 > resolver1.opendns.com.domain: 14223+% [1au] PTR? 4.1.168.192.in-addr.arpa. (53)
> E..Q..@.@........C...S.5.=..7............4.1.168.192.in-addr.arpa.......)........
> 19:40:12.001411 IP hostname.51647 > resolver1.opendns.com.domain: 2501+% [1au] PTR? 4.1.168.192.in-addr.arpa. (53)
> E..Q..@.@........C.....5.=.Z	............4.1.168.192.in-addr.arpa.......)........
> 19:40:12.001885 IP hostname.33104 > resolver1.opendns.com.domain: 30929+% [1au] PTR? 4.1.168.192.in-addr.arpa. (53)
> E..Q..@.@........C...P.5.=..x............4.1.168.192.in-addr.arpa.......)........
> 19:40:12.002412 IP hostname.47231 > resolver1.opendns.com.domain: 46563+% [1au] PTR? 4.1.168.192.in-addr.arpa. (53)
> E..Q..@.@........C.....5.=j{.............4.1.168.192.in-addr.arpa.......)........
> 19:40:12.004238 IP hostname.57292 > resolver1.opendns.com.domain: 61082+% [1au] PTR? 4.1.168.192.in-addr.arpa. (53)
> E..Q..@.@........C.....5.=
> w.............4.1.168.192.in-addr.arpa.......)........
> 19:40:12.008187 IP hostname.49786 > resolver1.opendns.com.domain: 14681+% [1au] PTR? 4.1.168.192.in-addr.arpa. (53)
> E..Q..@.@........C...z.5.=.
> 9Y...........4.1.168.192.in-addr.arpa.......)........
> 19:40:12.008926 IP hostname.53171 > resolver1.opendns.com.domain: 24423+% [1au] PTR? 4.1.168.192.in-addr.arpa. (53)
> E..Q..@.@........C.....5.=.._g...........4.1.168.192.in-addr.arpa.......)........
> 19:40:12.009629 IP hostname.37811 > resolver1.opendns.com.domain: 55231+% [1au] PTR? 4.1.168.192.in-addr.arpa. (53)
> E..Q..@.@........C.....5.=mk.............4.1.168.192.in-addr.arpa.......)........
>