No Stupid Questions

www was never necessary. It was used to distinguish other connection methods for the user(imagine ftp://, mail://, gopher://, etc) but you could always choose to route your domain(and any subdomain) to your web server. It remained part of marketing because it was what people expected. People kept using it in communication because they thought it was required.

ww1. or wwtubulartitty. could be routed to any web directory/page, sometimes maintainers will use ww1/ww2/etc to show that it's routing to an alternate version of the site(like language, location, etc.).

If you visit a site that only works with www. and not without, it's almost always because the person setting up the server screwed up.

There's two things at play here.

First, www originated in a time when the web was not synonymous with the internet. Gopher, FTP etc were a much larger part of peoples daily internet usage, and servers would have different subdomain names to account for that. ftp.tld.edu, gopher.tld.edu and www.tld.edu were all domains you might see for a single server for example. Then of course, the web grew, and the other protocols became less relevant, but the www stuck around. One of the reasons you're seeing less of it, is because that tradition is slowly fading away given its loss of daily relevance.

The other reason you're seeing less of it is that browsers often just hide it even when it's there. And that of course, will create more future instances of servers just dropping it completely.

Back when people still hosted their own email and web pages and domain controllers etc, it was more common to break it out into subdomains. The www subdomain was for the web stuff that the webmaster would administer. Nowadays everything is outsourced, and you just point your main domain ar whatever webhosting company you're using.

But it was always possible to have a normal A record on your main domain and have a webserver listen to its port 80.

I guess at some point everybody got so used to the world wide web just being there and every business being on it, that using the cool alliteration didn't feel necessary anymore.

Hey something I can answer!

TLDR: Because most owners of domains want their emails to have the same root (e.g.: bobby@acme.com as the email and acme.com as the website)

TLDR word salad: RFC rules restricts root domain CNAME records from coexisting with other DNS record types. Early internet bypassed this by pointing the website to subdomain www.example.com with a CNAME record; while hosting MX record at the root example.com Modern dns services have CNAME flattening which dynamically responds to an A record query at the root example.com with multiple ips

Also DNS is complicated

Some of the comments here describe the results of what happened but do not touch on the reason behind why www was common and why it is not anymore

The reason is very boring: because the rules say so. Specifically https://www.rfc-editor.org/info/rfc1034/ "If a CNAME RR is present at a node, no other data should be present; this ensures that the data for a canonical name and its liases cannot be different."

To discuss this further we need to breakdown what is part of the url in the first place so we don't mix things up. e.g. https://www.google.com/

https --> specifies the protocol here its http encrypted over TLS (SSL if your old)

: --> separates the protocol from the rest of the url

// --> fun hold over https://archive.nytimes.com/bits.blogs.nytimes.com/2009/10/12/the-webs-inventor-regrets-one-small-thing

www --> subdomain

google.com --> root domain

.com --> top level domain https://en.wikipedia.org/wiki/List_of_Internet_top-level_domains

Now for some common DNS address types you are probably already familiar with are

A records (amazon.com translates to ipv4 98.87.170.71)

AAAA records (google.com translates to ipv6 2607:f8b0:4004:c1f::71)

MX record (tells where your email goes to)

CNAME record (points to another DNS record name - usually an A record)

So why does a domain restriction on CNAME interfere with a website?

Because most owners of domains want their emails to have the same root.

And the rules do not allow for the root domain name to have both a CNAME and a MX record

For example, to have bob@amazon.com work.

A top level MX record for amazon.com must be published.

If an MX record for amazon.com exists CNAME can not exist.

So in the early days of the internet, a compromise standard was made.

MX records live at the root (eg: amazon.com) to direct mail for bob@amazon.com

CNAME records live at www. subdomain (eg: www.amazon.com) to direct web traffic

Why not just drop the CNAME at the root?

Use MX for mail at the root and A record at the root for website!

This will work perfectly fine actually. There's nothing functionally wrong with this.

In fact you can have your root A record round robin to several ips.

So your traffic can be roughly distributed at the DNS level across a few computers.

But this is generally a bad idea (without DNS health checks and other newer fancy things)

Because the actual computer behind your ip will inevitably crash, or update, or die, or reboot.

And now your website is fully down (1 ip) or partially down (1/3 of all traffic for example if you published 3 ips)

Why use CNAMEs at all?

Usually the CNAME record will point to some sort of load balancer. Think of this as router, it takes traffic in and sends it down to individual computers. If a computer dies, it takes it off from the available pool of computers; so that your traffic will hopefully live (session cache layer, etc, etc)

So in the old days DNS looked like this

MX record --> mail

CNAME record --> A record load balancer ips --> fleet of computers with internal ips added and dropped by lb

How does modern internet get on with root web traffic?

Some smart people got tired of typing www all the time so they invented CNAME flattening (DNS flattening) The DNS service provider, will dynamically update, and serve a fleet of individual ips as A records to the root domain lookup.

So now DNS looked like this

MX record -> mail

A record that keeps updating -> load balancer ips -> fleet of computers internal ips added and dropped by lb

Isn't that similar to old days? Why don't I just update my A records myself in the old days? Wouldn't that be the same?

That's actually exactly the same. The only problem with doing it yourself in the old days is DNS is hard.

DNS is basically a globally distributed cache managed at different layers by different people.

You COULD update the A records constantly yourself. You can even set your own record TTL to be 0 or 60seconds. However, random guy halfway across the world using budget ISP will not see your DNS update propagate to them for a few hours, sometimes 24 hours in worst case scenarios.

Modern DNS service providers (cloudflare, aws route53, etc, etc) has their own DNS hosted nodes distributed across the world for you so they auto update the records constantly for you to ensure no stale DNS hits if possible.

Practical Validation:

Since DNS is public you can run some queries yourself to see how DNS is managed by large companies

I'll use amazon.com as example root MX record: https://mxtoolbox.com/SuperTool.aspx?action=mx%3Aamazon.com&run=toolpage

--> this is what makes your mail work

root A record: https://mxtoolbox.com/SuperTool.aspx?action=a%3Aamazon.com&run=toolpage

--> this is CNAME flattening of the root

--> note the 3 ips - these are the dynamic ips of the load balancer for the region mxtoolbox is running in

root CNAME record: https://mxtoolbox.com/SuperTool.aspx?action=cname%3Aamazon.com&run=toolpage

--> does not exist! because it can't. MX record already lives here

subdomain CNAME record: https://mxtoolbox.com/SuperTool.aspx?action=cname%3Awww.amazon.com&run=toolpage

--> this exists! to route traffic to the web server

--> this is going to be some weird address <randomstring>-frontier.amazon.com this is some CDN that amazon uses to push traffic as close to the edge location where you are at to reduce page load times because physics exists

It's still there, you just don't need it since it's usually a given. Like how you didn't need to actually type out "http://" back in the day.

I’ve always made the ‘www.’ work for any site I’ve administered, but they immediately redirect with a 301 to the same url without it. It’s never been necessary, and I’ve always found it an eyesore.

Start with reading the documentation that explains this config:

RewriteCond %{HTTP_HOST} ^www\.(.*)$ [NC]
RewriteRule ^(.*)$ http://%1$1 [R=301,L]

The company owns the "example.com" domain name and can put what they want before it. The "www." part (which stands for World Wide Web) was a convention for the company to put their website on, as other subdomains may be used for other services than websites. As time went on, companies started to make the "example.com" itself point to the website as it is shorter and easier to type/remember, and made the "www.example.com" redirect you to "example.com" for retrocompatibility

In addition to all the good answers, there also the case that most browsers just hide it nowadays. Go to google.com, you'll see only that text in the URL field, the http(s)://www part is only shown when you click into the field, because as many have already said, it's redundant in today's infrastructure

It’s been “hidden” since Chrome v95 or something. Also, many companies might just host their web service on their main domain name.

Also, hit Ctrl+Enter in any browser and it’ll tack that right on it and goto the webpage or hit a redirect or 5…whatever their architect setup.

google.com may be a CNAME to www.google.com (for example).

The www (or whatever hostname) is just to balance the web traffic from the other Internet services, like SMTP, POP3, IMAP, FTP, etc.

I know its not necessary but I still type it because I'm old and have muscle memory

www. plays in my head a fair bit. It's that song that has the ICQ Uh Oh sound in it.