Ever wonder how the internet works? Why you can type in Google.com and it takes you straight to Google’s homepage or what the difference between https:// and http:// is? This is going to be an episodic post that answers most of the basics of how the internet really works in layman’s terms and what really is happening when you press go and its not Al gore inventing the internet or a series of tubes (that’s filled with cats.)
Behind the Scenes of the Internet “What is a Domain Name?”
A domain is something as simple as http://www.google.com its easy to remember, catchy and can be said in a sentence; it takes you to a website it’s allot easier to remember than Googles real address which is http://18.104.22.168 That will take you to google’s homepage as its interpreted by your computer. Its like Speed dial! You remember the persons name on the phone today but you may not remember their number!
Now domains come in all sorts of extensions .COM, .NET, .ORG, .ME etc… etc there are HUNDREDS of extensions known as Top Level Domains (TLDs) there are also Country Code Top Level Domains (ccTLDs) which are for .US (United States) .CA (Canada) .co.uk (United Kingdom).
A top-level domain (TLD) is the part of the domain name located to the right of the dot (” . “). The most common TLDs are .com, .net, and .org. Some others are .biz, .info, and .ws. These common TLDs all have certain guidelines, but are generally available to any registrant, anywhere in the world.
There are also restricted top-level domains (rTLDs), like .aero, .biz, .edu, .mil, .museum, .name, and .pro, that require the registrant to represent a certain type of entity, or to belong to a certain community. For example, the .name TLD is reserved for individuals, and .edu is reserved for educational entities.
Country-code TLDs (ccTLDs) represent specific geographic locations. For example: .mx represents Mexico and .eu represents the European Union. Some ccTLDs have residency restrictions. For example, .eu requires registrants to live or be located in a country belonging to the European Union. Other ccTLDs, like the ccTLD .it representing Italy, allow anyone to register them, but require a trustee service if the registrant is not located in a specified country or region. Finally, there are ccTLDs that can be registered by anyone — .co representing Colombia, for example, has no residency requirements at all.
So lets discuss .COM’s since they are so prevalent, the .COM extension belongs to Verisign known as a “Registry”(they also operate .NET) but you don’t buy a .COM from Verisign you get it through a company like Go Daddy which is known as a “Registrar” when you buy it from Go Daddy you become a “Registrant.” The easiest way to explain this is you don’t buy a car directly from the BMW factory you go through a dealership and buy it. When you need service and support you call the dealership.
Now a domain can do ac ouple things it can….
- Take you to a website
- Be a shortcut to another website
So now that the above makes a bit more sense what is a Sub Domain?
This blog is a subdomain http://paul.cerrone.me of http://cerrone.me. WWW is considered a Sub Domain and its not critical to typing in to get to a website (this was retired in the early 90’s). Sub Domains can be used like a domain they can go to the same place like WWW, a different place like my website or be used as a shortcut to access other applications. When you OWN the domain you can create any subdomain you wish and have it do something different.
The biggest use for this (for me at least) is the ability to give anyone a website at http://cerrone.me you can have bob.cerrone.me billy.cerrone.me or peter.cerrone.me and they can all be separate entities! or setup a different application than your main website if the two can’t function together! That and I’m far too cheap to keep registering domains they can cost anywhere from 8$ – 100$ yearly and that gets hard on the pocket!
What makes the domain work?
This is the hardest to answer easily without going too far overboard it’s Nameservers and Zone Files.
Nameservers are the Internet’s equivalent to phone books. A nameserver maintains a directory of domain names that match certain IP addresses (computers). The information from all the nameservers across the Internet is gathered in a central registry.
Nameservers make it possible for visitors to access your website using a familiar domain name, instead of having to remember a series of numbers.
So its a virtual phonebook to dial your friends! that leaves Zone Files
Zone files organize the zone records for domain names and subdomains in a DNS server. Every domain name and subdomain has a zone file, and each zone file contains zone records. These files, editable in any plain text editor, hold the DNS information linking domain names and subdomains to IP addresses. Zone files usually contain several different zone records.
NOTE: Although domain names might have subdomains, the zone files for subdomains are not considered sub-zone. All zone files are separate entities and do not have a hierarchical structure.
The most common records contained in a zone file are start of authority (SOA), nameserver, mail exchanger, host, and CNAME. These are described below.
Start of Authority (SOA) — Required for every zone file, the SOA record contains caching information, the zone administrator’s email address, and the master name server for the zone. The SOA also contains a number incremented with each update. As this number updates, it triggers the DNS to reload the zone data.
Name Server (NS) — The NS record contains the name server information for the zone.
Mail Exchanger (MX) — The MX record provides the mail server information for that zone to deliver email to the correct location.
Host (A) — Uses the A record to map an IP address to a host name. This is the most common type of record on the Internet.
Canonical Name (CNAME) — A CNAME is an alias for a host. Using CNAMEs, you can have more than one DNS name for a host. CNAME records point back to the A record. When you change the IP address in your A record, all CNAME records for that domain name automatically follow the new IP address.
Text (TXT) — This is an informational record. Use it for additional information about a host or for technical information to servers.
Service Records (SRV) — SRV records are resource records used to identify computers hosting specific services.
AAAA — AAAA records store a 128-bit Internet Protocol version 6 (IPv6) address that does not fit the standard A record format. For example, 2007:0db6:85a3:0000:0000:6a2e:0371:7234 is a valid 128-bit/IPv6 address.
Your brain may have just exploded from a technical overload here but really its like saying the I live at 123 Main Street, my phone number is (480)555-5555 and my PO Box is P.O Box 456
It tells the domain Where to go, where sub domains go where to send email, and then some security stuff. its really just a map of where to go!
Hopefully this made a little sense next up on Behind the Scenes of the Internet – Websites & Email!