Tech Musings

Monday, March 12, 2007

Virtual Hosts, DNS, Domain Names and OS X Server

Setting up virtual hosts with DNS on OS X Server was an intimidating prospect. I don't have a sandbox with an outside IP address to test on, so all experimentation related to virtual hosting would need to take place on my production server. Scary. And THIS is why I didn't know beans about this subject... until now!

Over the years I've purchased domain names and tied them into Web sites I've housed with hosting services, but I was not fully versed in the details of how this would work when everything actually resided on my own server. In other words, I was somewhat mystified by DNS and virtual hosting. Also, I've read a multitude of articles on how to set up virtual hosting on Apache, but many seemed overly verbose and difficult to apply to the OS X Server environment and its kludgy (klugy?) GUI.

Apple implemented its own flavor of Apache with OS X Server which has caused me many a headache over the years. Yet, to my chagrin, I don't have easy physical access and control to re-install a different OS on my Web server... if I did you can bet the house I would choose something other than OS X Server to run my Web services!

My other consideration was SOE or search engine optimization. I have a multitude of domain names I want to tie into my site, but I don't want to be penalized by Google or the other big players for promoting redundant content. Thus, I wanted to make sure I set up aliasing correctly so search engines would not find duplicate versions of my site.

Now, there a few different ways to set up virtual hosting on OS 10.3+ server. I originally contemplated trying it with virtual aliasing which was described by kiddailey in this post on oreillynet.com. But he didn't reference the Server Settings GUI which served me pause.

So, I started by posting a general probing question in the apple discussion forum. Part of the problem was that I wasn't exactly sure how to ask for help because I didn't know enough to know what to ask!! This is evident in the discussion thread. I wanted to use the Server Settings GUI to set it up because I was afraid to muck around in the Apache config files for fear of breaking the production server beyond repair.

Based on the feedback I received, I decided to forge ahead and use the GUI to add a second site. My greatest fears were realized as my main site went offline instantly. Nice. I immediately posted a cry for help on the apple board, again. As soon as I hit the submit button I started reading another discussion which helped me finally get my arms around how Apache handles virtual hosting. Conceptually, I was under the impression Apache needed to host each virtual site on its own port number or designated IP address. How could two sites share the same IP and port number? Well, they can because Apache negotiates incoming requests (i.e. traffic) according to what it's instructed to do in the configuration files. This is a pretty good article written in easy-to-understand language that explains the process: http://www.apacheweek.com/features/vhost

Based on what I read in the second discussion, I came to the understanding that ALL sites on OS X Server are set up as virtual hosts. In fact, each site that resides on a box has its own site configuration file located in /etc/httpd/sites. When you create a new site and enable it in Server Settings under Web Services, a new configuration file for that site is generated. It will probably look something like this 0001_214.43.212.41_80_photography.us.com.conf. Any directive featured in the main httpd.conf file can be overruled by directives in each site's individual configuration file. All sites can share the same port number because Apache will listen for an incoming request on a domain name and route that request to the appropriate site to fetch its content. So, when a request comes in on http://photography.us.com/page_1.html, Apache will actually recognize (i.e. read) the domain name (photography.us.com) in the headers sent by the browser and route the request on the server to the appropriate directory according to what it has been told in its config files. I'm beginning to truly appreciate how smart this piece of software really is!!

In theory, both sites should be able to be assigned to the same port, but this wasn't working for me. When I assigned my second site port 8080, both sites finally came online. However, after coming across a domain management service called EditDNS and entering the IP addresses for my server, I was stuck. Where do I input the port number 8080 in the class A record for my domain name? I tried using a AAAA record but was told these were reserved for only IPv6, and I had an IPv4 address (reference this post on nerdie nets). You can't include port numbers in DNS records. Sheee-it.

It turns out that Performance Cache was turned on in Server Settings which was causing all of my problems. After unchecking this box and assigning both sites to port 80, it worked.
unchecking the performance cache in OS X Server Settings for Virtual Hosting
I also needed to remove the quotes around the Include /etc/httpd/sites/*conf in httpd.conf, which, for some ridiculous reason, was not automatically done when I added another site using the server settings GUI. DAMN YOU APPLE! So much of my frustration has stemmed with OS X Server and their damn GUI!!!
Remove the quotes around this Include statement in httpd.conf for virtual hosts to work in OS X Server
The final piece of the puzzle for me was to properly set up domain aliases and 301 redirects. I added all my additional domain names in the Web Server Aliases window under the "Aliases" button separated by hard returns, then added 301 permanent redirects in the .htaccess file. For example, if you want the www version of your domain name to resolve to the non-www version, you add the www version in the server alias window and then enter a 301 redirect in the .htaccess file.
Adding additional domain names into the Sites Aliases window of Server Settings
Entries in my site's .htaccess file:

Options +FollowSymlinks
RewriteEngine on
RewriteCond %{HTTP_HOST} ^www\.photography\.us\.com$
RewriteRule (.*) http://photography.us.com$1 [R=permanent,L]


Options +FollowSymlinks

RewriteEngine on
RewriteCond %{HTTP_HOST} ^www\.san-diego-photography\.org$
RewriteRule (.*) http://photography.us.com$1 [R=permanent,L]

Options +FollowSymlinks
RewriteEngine on
RewriteCond %{HTTP_HOST} ^san-diego-photography\.org$
RewriteRule (.*) http://photography.us.com$1 [R=permanent,L]

Options +FollowSymlinks
RewriteEngine on
RewriteCond %{HTTP_HOST} ^www\.san-diego-photographs\.com$
RewriteRule (.*) http://photography.us.com$1 [R=permanent,L]

Options +FollowSymlinks
RewriteEngine on
RewriteCond %{HTTP_HOST} ^san-diego-photographs\.com$
RewriteRule (.*) http://photography.us.com$1 [R=permanent,L]

1 Comments:

  • Thanks a lot for this fine post. I love reading more about what can be done with an OS X Server. It is very easy to find information regarding Apache servers on a Linux machine but it is much harder to find good information regarding OS X.

    Keep up the good work!

    Domain Registrar
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    By Blogger Nebo, at 1:16 PM  

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