Note About Domain and DNS

You might have seen domains with a dot in the end:

archive.casouri.co.uk.

This not only is a valid domain, but also a better (more concise) format than the one without the dot in the end. The ending dot is like the root directory /, it marks the root of the domain. And a domain with that dot in the end is considered absolute, just like an absolute path.

Similarly, a domain without an ending dot is considered relative. So I can totally add something after it like archive.casouri.co.uk.what.is.this.com, just like what I can do to a relative path.

DNS resource records are basically mapping files that tell the DNS server which IP address each domain is associated with.

Here are the most commonly used types of DNS records:

A record

An A record maps a domain name (e.g., www.example.com) to an IP address and usually starts with www.

CNAME record

A Canonical Name (CNAME) is a type of record in the DNS that is used to specify that a domain name is an alias for another domain or sub domain. I used a CNAME record to link archive.casouri.co.uk. to casouri.github.io.

MX record

A mail exchanger (MX) record refers to a resource record (RR) that routes traffic to an email server. More on https://en.wikipedia.org/wiki/MX_record.

TXT record

A text record (TXT record) is a type of resource record in the DNS that lets you associate plain text with a domain.

A DNS zone represents a range of IP addresses in a domain name space.

A domain provider, or domain name registrar, is a company or organization that manages the assignment of domain names. For me it's gandi.net.

The server that translates domains into IP addresses.

A text file describes mapping between domain and IP.