google.com is a domain,
bing.com is another.
There can be sub domains, like
maps.google.com, but they all belong to the same
When user put
www.example.com into the browser, the browser does not know about that "example" website, it will ask the DNS(Domain Name System) server where to go. DNS server will lookup
www.example.com in its records, if it finds one, it will "resolve" the string into an IP address, so the browser can send the request to that IP and retrieve the content(HTML, images, etc).
There are a few options, the prices and capabilities vary.
- can be very cheap for the first year
- price may go up for the following years, keep an eye on your bills.
- your information is public
- transparent and consistent price: $12 for .com, for example
- you can make your information private without extra expense.
Once you have your domain registered, you can config the subdomains and other settings. A few terms to clarify:
- A: map from subdomain to IPv4
- AAAA: map from subdomain to IPv6
- CNAME: map from subdomain to other domain or subdomain
The following sections illustrate how they can be used.
Use A(IPv4) or AAAA(IPv6) record since you know the IP
You can also point multiple subdomains to the same IP. All of the traffic to
app.mydomain.com will be sent to that IP, then it is HTTP server's job to find the right sub domain(
By using Heroku or Github Pages or GitBook, you do not know the IP, so use
CNAME to create an alias for each
Using A/AAAA/CNAME will not modify URL, however
Forward will redirect user to a different URL