In fact it's slightly simpler in that both a.example.com and b.example.com are public domains. (This is why I put them in the global config to begin with; these domains will resolve over any nameserver.) Thus it's not so much that queries for b.example.com don't go to W.X.Y.Z; it's that they don't go anywhere.
More precisely: By default, ie. without a Domains= line in resolved.conf, b.example.com resolves correctly: the query goes to some random nameserver, which can resolve it because it's a public domain. With Domains=b.example.com, b.example.com fails to resolve, and systemd- resolve reports "No appropriate name servers or networks for name found" without querying any server. (At least I cannot observe any DNS or LLMNR traffic on the network connection of my test VM.) -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to systemd in Ubuntu. https://bugs.launchpad.net/bugs/1714803 Title: Search list in resolv.conf breaks resolving for that domain Status in systemd package in Ubuntu: Incomplete Bug description: Ubuntu 17.04 systemd 232-21ubuntu5 Adding a domain to the search list in /etc/resolv.conf breaks resolving for that domain. Not only does the search list not get used as expected, but host names in the domain cannot be resolved by systemd-resolved at all. I just ran into this after upgrading from ubuntu 16.04 to 17.04 which enabled systemd-resolved. I have for a long time used resolveconf to add a 'search my-domain'-line to my /etc/resolv.conf. Example of expected behaviour. With Googles DNS server (8.8.8.8) and ubuntu.com in the search list in /etc/resolv.conf. Both dig and systemd-resolve can resolve www.ubuntu.com and www: $ cat /etc/resolv.conf nameserver 8.8.8.8 search ubuntu.com $ dig +nostat +nocmd www.ubuntu.com ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 55037 ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1 ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 512 ;; QUESTION SECTION: ;www.ubuntu.com. IN A ;; ANSWER SECTION: www.ubuntu.com. 501 IN A 91.189.89.115 $ dig +search +nostat +nocmd www ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 25772 ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1 ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 512 ;; QUESTION SECTION: ;www.ubuntu.com. IN A ;; ANSWER SECTION: www.ubuntu.com. 382 IN A 91.189.89.103 $ systemd-resolve www.ubuntu.com www.ubuntu.com: 91.189.89.115 -- Information acquired via protocol DNS in 2.7ms. -- Data is authenticated: no $ systemd-resolve www www: 91.189.90.59 (www.ubuntu.com) -- Information acquired via protocol DNS in 3.8ms. -- Data is authenticated: no Ubuntu 17.04 default config, with the systemd-resolved name server in /etc/resolv.conf and no search list. www.ubuntu.com can still be resolved correctly: $ cat /etc/resolv.conf nameserver 127.0.0.53 $ dig +nostat +nocmd www.ubuntu.com ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 64646 ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1 ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 65494 ;; QUESTION SECTION: ;www.ubuntu.com. IN A ;; ANSWER SECTION: www.ubuntu.com. 482 IN A 91.189.89.110 $ systemd-resolve www.ubuntu.com www.ubuntu.com: 91.189.90.58 -- Information acquired via protocol DNS in 18.2ms. -- Data is authenticated: no Broken behaviour, using the systemd-resolved name server and specify ubuntu.com in search list. Resolving fails for www.ubuntu.com and www, both using dig (DNS) and using sytemd-resolve: $ cat /etc/resolv.conf nameserver 127.0.0.53 search ubuntu.com $ dig +nostat +nocmd www.ubuntu.com ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 33334 ;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1 ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 65494 ;; QUESTION SECTION: ;www.ubuntu.com. IN A $ dig +search +nostat +nocmd www ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 50588 ;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1 ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 65494 ;; QUESTION SECTION: ;www.ubuntu.com. IN A $ systemd-resolve www.ubuntu.com www.ubuntu.com: resolve call failed: No appropriate name servers or networks for name found $ systemd-resolve www www: resolve call failed: All attempts to contact name servers or networks failed To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1714803/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
