How to check DNS Follow

Navigate to: https://dnschecker.org/

Enter in your domain:

You can also run command-line tools. 

Dig the domain www.section-demo.net and verify it is a CNAME.

➜ Section dig www.section-demo.net

; <<>> DiG 9.10.6 <<>> www.section-demo.net
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 3641
;; flags: qr rd ra; QUERY: 1, ANSWER: 6, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;www.section-demo.net. IN A

;; ANSWER SECTION:
www.section-demo.net. 1800 IN CNAME www.section-demo.net.c.section.io.
www.section-demo.net.c.section.io. 300 IN CNAME 43bc02af359540143b573e32bc57d93c.e.ns1.sectionedge.com.
43bc02af359540143b573e32bc57d93c.e.ns1.sectionedge.com. 300 IN CNAME do-sfo-k9.ep.section.io.
do-sfo-k9.ep.section.io. 120 IN A 159.65.106.184
do-sfo-k9.ep.section.io. 120 IN A 167.99.105.35
do-sfo-k9.ep.section.io. 120 IN A 159.65.107.188

;; Query time: 84 msec
;; SERVER: 192.168.42.1#53(192.168.42.1)
;; WHEN: Wed May 19 11:38:26 PDT 2021
;; MSG SIZE rcvd: 249

Dig the mysection.io bare domain (otherwise known as apex or root domain) and verify it's an A record and is using one of Section's anycast networks.

➜ Section dig mysection.io

; <<>> DiG 9.10.6 <<>> mysection.io
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 50477
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;mysection.io. IN A

;; ANSWER SECTION:
mysection.io. 900 IN A 45.154.183.183

;; Query time: 317 msec
;; SERVER: 192.168.42.1#53(192.168.42.1)
;; WHEN: Wed May 19 11:41:08 PDT 2021
;; MSG SIZE rcvd: 57