ICRealtime How-to Notes 96048
General
Dynamic Domain Name System (DDNS) Information
You
may have heard about DDNS before, but if you’re reading this you probably don’t
know how it works or how it can benefit yourself. Before we explain what a
particular DDNS will do, let’s briefly touch on the Internet Protocol (IP).
The internet
that we’ve come to know is currently being run using the TCP/IP protocol
(which is actually a group of two commonly used protocols). For the purpose of
this walkthrough, you don’t need to understand exactly what these two protocols
do, but more so the actual purpose they serve. The TCP protocol is a
set standard on how devices (DVR’s, printers, computers, etc.) communicate, and
the IP protocol is the current standard for addressing. Each device
that is on a TCP/IP based network will have a logical IP address.
A real world analogy would use the US Postal Service. You could compare the
TCP protocol to the mail carriers that deliver your mail, and the IP address to
your house number. This scenario works fine most of the time, but what if your
house number changed daily? This could cause several problems, but before
discussing these let’s cover why this may happen and the two flavors of IP
addresses.
When you
purchase an internet service, the provider will register and issue an IP
address (traditionally, to your modem), which allows you to communicate and to
be located on the internet. The ISP (internet service provider) can
either statically assign your IP address, or allow it to be dynamically
assigned.
Static – A
static IP will not change. This is beneficial when networking your DVR, as you
will always know the address to connect into your machine. ISP’s will usually
reserve these addresses for business accounts, or for accounts who explicitly
request one.
Dynamic –
A dynamic IP will change, or release itself, at a given interval. These are
the addresses given to everyone else. While these kinds of IP addresses work
fine for nominal internet use, they will prove troublesome if you have part of
your surveillance system linked to it! “How can I consistently connect to an
IP that itself is inconsistent?”, you may ask. The answer lies in Domain
Names, and specifically, a Dynamic Domain Name System.
We’ve
already explained that a computer on a network can be numerically named with an
IP address. Similar to this, a computer can also have a domain name that will
identify itself to a network. To access this website, you typed in our domain
name: www.lowvoltagesecurity.com. In turn,
your computer resolved the domain name www.lowvoltagesecurity.com
to the IP address of our web server, and once connected, it displayed our
homepage. Although it may not immediately be obvious, a domain name has two
advantages over and IP address. First, assuming you have a fairly simple
domain name, it’s easier to remember.
Example: www.lowvoltagesecurity.com vs. 64.202.189.131.
Both are logical addresses for the location of our web server.
The
second benefit is much more than just convenient. Even if a domain name is
linked to a dynamic address, that specific domain name will always remain
the same. This factor will overcome the downfall of a dynamic IP address.
If you have a DDNS name linked to a dynamic IP address, you will always be able
connect to that domain name, and in turn, access whatever it is you have linked
to that IP address.
DDNS Services
The
two largest DDNS services IC Realtime recommends include www.tzo.com and www.dyndns.com.
These two services in particular have an excellent support staff who can walk
you through registering a DDNS name, as well as the best way to setup the
required software. This software can be setup either on a dedicated computer
within that network, or actually on the router itself.
Above is an example of a router that
supports DDNS. After registering with a DDNS service, you can input your
credentials here to have your router automatically update your dynamic IP
address. You can see also that this brand has their own DDNS service free of
charge!
