Do you see the same behavior when you execute your dig query without the trailing dot?
Thanks, Stephen > > On Sep 6, 2019, at 3:11 PM, Chip Marshall via NANOG <nanog@nanog.org> wrote: > > > > Hello, I'm seeing an oddity when doing DNS lookups for www.google.com from > > our > > London datacenter, and I'm curious if other people are seeing the same > > behavior. > > > > It appears that when we ask for www.google.com. we sometimes get an answer > > that only contains records for www-anycast.google.com., which our resolver > > ignores as they don't match the query. > > > > As seen with dig: > > > > ``` > > # dig @ns1.google.com. www.google.com. aaaa > > > > ; <<>> DiG 9.10.3-P4-Ubuntu <<>> @ns1.google.com. www.google.com. aaaa > > ; (2 servers found) > > ;; global options: +cmd > > ;; Got answer: > > ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 42641 > > ;; flags: qr aa rd; QUERY: 1, ANSWER: 4, AUTHORITY: 0, ADDITIONAL: 1 > > ;; WARNING: recursion requested but not available > > > > ;; OPT PSEUDOSECTION: > > ; EDNS: version: 0, flags:; udp: 512 > > ;; QUESTION SECTION: > > ;www.google.com. IN AAAA > > > > ;; ANSWER SECTION: > > www-anycast.google.com. 300 IN AAAA 2001:4860:4802:34::75 > > www-anycast.google.com. 300 IN AAAA 2001:4860:4802:38::75 > > www-anycast.google.com. 300 IN AAAA 2001:4860:4802:36::75 > > www-anycast.google.com. 300 IN AAAA 2001:4860:4802:32::75 > > > > ;; Query time: 7 msec > > ;; SERVER: 216.239.32.10#53(216.239.32.10) > > ;; WHEN: Fri Sep 06 19:05:32 UTC 2019 > > ;; MSG SIZE rcvd: 167 > > ``` > > > > So far I've observed this with A and AAAA queries. It's my understanding > > that > > without a CNAME record in the answer, the resolver is doing the right thing > > by > > ignoring the answer, as there's no linkage between www and www-anycast. > > > > Is this broken, or is this just some weird DNS trick I've not come across > > before? > > You may want to post on dns-operations instead. > > Can you do a dig +trace www.google.com instead, that would be more > instructive about whatтs happening at each layer o f the delegation. > > - Jared
