Web site checking
There are several checks that you may want to do during the development of a website.
If you change the DNS of a domain, you my wish to know when it has propagated.
DNS Pro
https://www.whatsmydns.net
Status of your website’s SSL certificate
SSL Certificate
https://www.sslshopper.com
What s your IP address. Sometimes you may need to whitelist your own IP.
IP Address
https://www.whatismyip.com