Introduction
When you have your web site or application up and running behind a domain, it is often desirable to also allow your users access to it via the plain domain name and the www subdomain. That is, they should be able to visit your domain with or without the “www.” prefix, e.g. example.com or www.example.com, in a web browser, and be presented with the same content. While there are a variety of ways to set this up, the best solution, for consistency and SEO considerations, is to choose which domain you prefer, plain or www, and redirect the other one to the preferred domain. This type of redirect is called a Permanent Redirect, or “301 redirect”, and can be easily set up by properly configuring your DNS resource records and web server software.
This tutorial will show you how to redirect a www URL to non-www, e.g. www.example.com to example.com, with Apache on Ubuntu 14.04. We will also show you how to redirect in the other direction, from a non-www URL to www. The CentOS 7 version of this tutorial is available here.
If you want to perform this type of redirect with Nginx as your web server, you should follow this tutorial instead: How to Redirect www to non-www with Nginx on Ubuntu 14.04.
Prerequisites
This tutorial assumes that you have superuser privileges, i.e. sudo or root, on the server that is running Apache. If you don’t already have that set up, follow this tutorial: Initial Server Setup on Ubuntu 14.04.
It is assumed that you have Apache installed. If you do not already have this set up, there are several tutorials on the subject under the Apache tag.
You must be able to add records to the DNS that is managing your domain. If you do not already have a domain, you may purchase one from a domain registrar, and manage it with the registrar’s DNS or DigitalOcean’s DNS. In this tutorial, we will use the DigitalOcean DNS to create the necessary records.
Let’s get started by configuring your DNS records.
Configure DNS Records
In order to set up the desired redirect, www.example.com to example.com or vice versa, you must have an A record for each name.
Open whatever you use to manage your DNS. For our example, we’ll use the DigitalOcean DNS.
If a domain (also known as a zone) record does not already exist, create one now. The hostname should be your domain, e.g. example.com, and the IP address should be set to the public IP address of your Apache server. This will automatically create an A record that points your domain to the IP address that you specified. If you are using another system to manage your domain, you may need to add this manually.
Next, add another A record with “www” as the hostname (or “www.example.com” if the partial subdomain doesn’t work), and specify the same IP address.
When you have created both records, it should look something like this:
Note: This will also work with CNAME records, as long as the canonical name’s A record refers to the IP address of your Apache web server.
Now your server should be accessible via the www and non-www domain, but we still need to set up the redirect. We’ll do that now.
Enable Rewrite Module
In order to perform the 301 redirect, we will use the Apache mod_rewrite, or Rewrite, module. Doing so will ensure that your users can access your site with or without the www. prefix, and be redirected to the domain that you prefer.
First, enable the mod_rewrite module with this command:
sudo a2enmod rewrite
With the Rewrite module enabled, we can configure Apache with redirect rules using .htaccess files.
Enable .htaccess Files
Open your Apache configuration file for editing. On Ubuntu, the default configuration file is located at /etc/apache2/sites-enabled/000-default.conf, so we will use that in our example:
sudo vi /etc/apache2/sites-enabled/000-default.conf
Find the DocumentRoot of your site, and take a note of it. By default, it’s /var/www/html, so we will use that in our example configuration.
Add the following Directory directive to the configuration and be sure to substitute the DocumentRoot for the highlighted part:
Add to Apache configuration
<Directory /var/www/html>
Options Indexes FollowSymLinks MultiViews
AllowOverride All
Order allow,deny
allow from all
</Directory>
Save and exit.
Now restart Apache to put the change into effect:
sudo service apache2 restart
Now Apache is configured to read .htaccess files located anywhere under the /var/www/html directory. Let’s add our Rewrite rules now.
Configure Rewrite Module
As we mentioned earlier, we will configure the Rewrite module using an .htaccess file.
Change directories to your DocumentRoot, in our case, /var/www/html:
cd /var/www/html
Now open .htaccess for editing:
sudo vi .htaccess
Of course, if you haven’t created the file before, it will be blank. Depending on which direction you want to redirect, use one of the following options.
Option 1: Redirect www to non-www
If you want redirect users from www to a plain, non-www domain, insert this configuration:
.htaccess — www to non-www
RewriteEngine On
RewriteBase /
RewriteCond %{HTTP_HOST} ^www.(.*)$ [NC]
RewriteRule ^(.*)$ http://%1/$1 [R=301,L]
Save and exit. The changes should go into effect immediately. Note that if you are using HTTPS, you should update “http”, in the RewriteRule line, to “https”.
Use this curl command to ensure that the non-www domain redirects to the www domain (replace the highlighted part with your actual domain):
curl -I http://www.example.com
You should get a 301 Moved Permanently response, that shows the non-www redirect location, like this:
:HTTP/1.1 301 Moved Permanently
Date: Fri, 01 May 2015 21:18:33 GMT
Server: Apache/2.4.7 (Ubuntu)
Location: http://example.com/
Content-Type: text/html; charset=iso-8859-1
Of course, you should access your domain in a web browser (www and non-www) to be sure.
Option 2: Redirect non-www to www
If you want redirect users from a plain, non-www domain to a www domain, insert this configuration:
.htaccess — non-www to www
RewriteEngine On
RewriteBase /
RewriteCond %{HTTP_HOST} !^www. [NC]
RewriteRule ^(.*)$ http://www.%{HTTP_HOST}/$1 [R=301,L]
Save and exit. the changes should go into effect immediately. Note that if you are using HTTPS, you should update “http”, in the RewriteRule line, to “https”.
Use this curl command to ensure that the non-www domain redirects to the www domain (replace the highlighted part with your actual domain):
curl -I http://example.com
You should get a 301 Moved Permanently response, that shows the www redirect location, like this:
:HTTP/1.1 301 Moved Permanently
Date: Fri, 01 May 2015 21:18:33 GMT
Server: Apache/2.4.7 (Ubuntu)
Location: http://www.example.com/
Content-Type: text/html; charset=iso-8859-1
Of course, you should access your domain in a web browser (www and non-www) to be sure.
Conclusion
That’s it! Your Apache redirect is now configured properly, and your users will be able to access your web server via your non-www and www domain.
If you would like to understand more about mod_rewrite, the Apache feature that we used to implement the redirect, feel free to read this tutorial: How To Set Up Mod_Rewrite.
