Hi, TLDR: DNS request to dnsmasq with upper-case domain is handled differently if request is sent over TCP vs UDP
I run a server to forward "cluster.local" queries to another process: /usr/sbin/dnsmasq-k--cache-size=1000--no-negcache--dns-forward-max=1500--log-facility=---server=/cluster.local/ 127.0.0.1#10053--log-queries=extra--log-debug <http://127.0.0.1/#10053--log-queries=extra--log-debug> dnsmasq 2.86 with IP 10.64.0.7 1. When I run: dig +tcp kubernetes.default.svc.cluster.LOCAL @10.64.0.7 I get NOERROR but no data in the response. dnsmasq logs: I0913 06:15:04.790606 1 nanny.go:146] dnsmasq[86]: 44065 10.64.1.4/33015 query[A] kubernetes.default.svc.CLUSTER.LOCAL from 10.64.1.4 I0913 06:15:04.851065 1 nanny.go:146] dnsmasq[86]: 44065 10.64.1.4/33015 forwarded kubernetes.default.svc.CLUSTER.LOCAL to 169.254.169.254 As you can see dnsmasq doesn't modify the domain. Because it's a "CLUSTER.LOCAL" and not a "cluster.local" it's forwarded to the server 169.254.169.254 set in the /etc/resolv.conf. And not the --server=/cluster.local/127.0.0.1#10053 <http://127.0.0.1/#10053> 2. When I run exactly the same query but over UDP not TCP: dig kubernetes.default.svc.CLUSTER.LOCAL @10.64.0.7 I get NOERROR and correct response: kubernetes.default.svc.CLUSTER.LOCAL. 30 IN A 10.68.0.1 dnsmasq logs in this case: I0913 06:19:20.820425 1 nanny.go:146] dnsmasq[11]: 44471 10.64.1.4/49622 query[A] kubernetes.default.svc.CLUSTER.LOCAL from 10.64.1.4 I0913 06:19:20.820866 1 nanny.go:146] dnsmasq[11]: 44471 10.64.1.4/49622 forwarded kubernetes.default.svc.cluster.local to 127.0.0.1 In this case the domain in the query is changed to the lower-case and it matches "cluster.local" and forwards to 127.0.0.1 as expected. 3. When I run exactly the same query over TCP but fully lower-case it works as well. Is this a bug or intended behaviour or maybe I misunderstood the logs? Thanks!
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