Dynamic IP / Dynamic DNS – Working with Dynamic IP addresses
Most broadband ISP providers tend to issue
dynamic IP addresses for their residential customers. Static IP addresses are usually available
for a higher price and tend to be targeted for businesses.
Dynamic IP addresses are usually allocated
when your router connects to your ISP, and a new IP address is normally allocated
each time you disconnect and reconnect.
Some ISPs choose to cycle your allocated IP address after a fixed period
of time, this is seen as a way to encourage users to upgrade to a more
expensive static IP.
To run a web host, you need to have a fixed
address that is directly accessible from the internet. Luckily domain names can hide the
intricacies of whether you have a fixed (static) IP or a dynamic IP address.
There are some DNS (Domain Name Server)
providers that specialise in users that have dynamic IPs,
and hence have the infrastructure that allows the IP address to be updated
regularly.
I use Sitelutions
(http://www.sitelutions.com/) for my
DNS server who provide a reliable service and have a number of backup DNS
services in different geographic locations as a risk contingency. They provide an interface for updating your
domains IP address regularly along with many other services.
A quick Google can provide you a list of
many others.
Each Dynamic DNS provider will provide some
information on what the optimal settings are for TTL (time to live) for your
DNS A records. Your Dynamic DNS
provider is treated as the top level record of domain names to IP address
translation. Other DNS servers will
request refreshed records from this top level server every time the TTL
expires. This ensures that anyone who
looks up your domain name on the internet will get the correct IP.
One you have a provider that allows Dynamic
DNS, you will need to install a IP update program on
your Web Host.
I use Direct Update (http://www.directupdate.net/). This is a great program,
that can be installed as a service, which can be used to update any
number of virtual hosts and domain names.
I have mine set up to check my IP every 10
minutes and if it has changed to update by DNS entries on Sitelutions.
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