Jul 12 2010

No Static IP? Use DynDNS!

Some of us aren’t blessed (or perhaps cursed depending how you look at it) with a static IP address. For me, it’s a blessing that I do have one because I can run a whole bunch of servers (for VoIP, web servers, TF2 and VPN for instance) without having to keep updating an IP address. However, other people do not have that luxury and have to put up with remembering four magic numbers.

Luckily, there is a solution.

There is a great service that I use called DynDNS (or Dynamic DNS). Basically, you can sign up for a free account that will allow you to create a hostname (like purplecow.dyndns.org for example) that will point to your IP address. For those of you who don’t know what an IP address, it’s a unique set of four numbers that identify your computer on a network (such as your home network or a larger network like the Internet).

Now, numbers are fine for computers to find each other on the Internet but most of us might find it difficult to remember four numbers for all the sites we want to browse on the Internet. That’s why Domain Name System (DNS) was invented. DNS translates a hostname (like blog.mingersoft.com) to an IP address. Hostnames are typically comprised of a hostname (such as “blog” in blog.mingersoft.com”) and a domain name (which would be “mingersoft.com”).

So when it comes to creating your own hostname, DynDNS has a choice of nearly 80 domain names (like dyndns.org, dnsalias.net and homeip.net). Depending on what you are after, you might need to get a bit creative or try another domain name.

Another important option is the Time to Live (TTL) value. Basically, this dictates how long a hostname and its corresponding IP address is cached by a computer. The free account has two values on offer, specifically:

  1. 60 seconds (for connections with a dynamic IP address like dialup or mobile broadband connections),
  2. 4 hours (for connections that don’t change IP addresses very often or have a static IP address).

If you are unsure, you should go with the default option of 60 seconds. This is important as if your IP address changes, you want to be able to quickly find your new IP address using your hostname rather than waiting hours for the refresh to occur.

Now for the important bit – getting your hostname to map to your IP address.

Basically, there are two options:

  1. run a piece of software on a computer on your network (available for Windows, MacOS and *nix),
  2. configure your DynDNS capable router with your details.

Rather than reinvent the wheel, DynDNS has guides on how to configure their software here. The range of supported routers is also available here. In a nutshell, you need to do the following:

  1. select DynDNS as the service type (if required),
  2. type in your DynDNS username and password,
  3. type in your hostname,
  4. set the refresh interval (set this to a value equal to or under 28 days).

So if you have been wrestling with IP addresses, give this a shot – it might make your life much easier!

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