Mac OS X Leopard - ARCAism

Domain Name Tricks
Were you so inclined, you could set up a DNS server . . . but why? Chances are your registrar has
a name server, so providing you have a static outside IP address, you can simply have them point
to it and start welcoming visitors to your self-hosted web site.
However, not everyone has the need to spend the money on a static IP address. Especially
when you consider that the cost of getting one is greater than the cost of professional web hosting.
If you’re setting up a web host just because it’s fun, because you want to save money, or
because you’re doing local development, paying for a static IP address is overkill.
Custom Domains Without DNS
You can actually override DNS at a local level. Mac OS X maintains a list of known hosts in a
file called /private/etc/hosts. Editing this file will let you map web addresses to IP addresses.
Why would you do this?
First, looking at IP addresses all day is boring. That’s why DNS was invented, after all. It’s
much more fun to give your local network machines fun names at imaginary top-level domains.
Then you can surf over to http://mike.is.awesome.
Second, if you are developing web pages locally, you might run into a problem with absolute
paths. That is to say, if you have a link pointing to www.mydomain.com/somefile.php, your browser
will want to go to the remote version, rather than the local version you’re developing.
The hosts file is the first place your machine looks when it tries to resolve a domain. Rerouting
calls to mydomain.com or www.mydomain.com to your local machine is easy. Just open /private/
etc/hosts in your favorite text editor, and then add the following line:
127.0.0.1 mydomain.com www.mydomain.com
Just remember to edit the hosts file back to normal before trying to surf the Web, or strange
things might happen. For more information on the hosts file, invoke man hosts in Terminal.
CAUTION It’s OK to add things to the hosts file, but don’t edit any of the existing entries. The
system has that stuff there for a reason.
Dynamic DNS
CHAPTER 22 LEOPARD AS A WEB SERVER 397
What if you want to serve a personal web site from your home, but you don’t want to pay for a
static IP address? You could just update your registration every time your address changes, but
given the time it takes for DNS changes to propagate, you could be looking at a lot of downtime.
Even for a home project, that just looks sloppy.
A better option is to use a dynamic DNS service. There are many cheap-to-free services,
such as No-IP (www.no-ip.com/) and FreeDNS (http://freedns.afraid.org/), that will let you point
a domain name to your dynamic IP address. Unlike a standard name server, dynamic DNS services
keep a very short refresh time on their name servers, so changes propagate quickly.