Is there some way to inspect the Docker DNS server? It’s not behaving as expected.
Two different containers running on the same server. Same network (Macvlan), with neighboring public IP addresses. Same resolv.conf:
nameserver 127.0.0.11
options ndots:0
I can ping 127.0.0.11 from both containers. But when doing a DNS request, one of them times out.
Container 1:
root@test1:/# dig @127.0.0.11 google.com
; <<>> DiG 9.10.3-P4-Ubuntu <<>> @127.0.0.11 google.com
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 28557
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 4, ADDITIONAL: 5
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;google.com. IN A
;; ANSWER SECTION:
google.com. 250 IN A 216.58.204.46
;; AUTHORITY SECTION:
google.com. 42304 IN NS ns2.google.com.
google.com. 42304 IN NS ns3.google.com.
google.com. 42304 IN NS ns1.google.com.
google.com. 42304 IN NS ns4.google.com.
;; ADDITIONAL SECTION:
ns2.google.com. 215115 IN A 216.239.34.10
ns1.google.com. 215115 IN A 216.239.32.10
ns4.google.com. 215115 IN A 216.239.38.10
ns3.google.com. 215115 IN A 216.239.36.10
;; Query time: 0 msec
;; SERVER: 127.0.0.11#53(127.0.0.11)
;; WHEN: Mon Oct 30 23:02:12 UTC 2017
;; MSG SIZE rcvd: 191
Container 2:
root@test2:/# dig @127.0.0.11 google.com
; <<>> DiG 9.10.3-P4-Ubuntu <<>> @127.0.0.11 google.com
; (1 server found)
;; global options: +cmd
;; connection timed out; no servers could be reached
Querying Googles DNS servers:
root@test2:/# dig @8.8.8.8 google.com
; <<>> DiG 9.10.3-P4-Ubuntu <<>> @8.8.8.8 google.com
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 49681
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;google.com. IN A
;; ANSWER SECTION:
google.com. 299 IN A 172.217.23.14
;; Query time: 9 msec
;; SERVER: 8.8.8.8#53(8.8.8.8)
;; WHEN: Mon Oct 30 23:20:19 UTC 2017
;; MSG SIZE rcvd: 55
Version 17.09.0-ce