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Broadband - Exchange Email Access (both Remote Access to |
Dynamic DNS
If you want to access your machine that is always connected to the Internet while away from the machine, you would have to remember it's IP address. A more convenient method would be to give it a friendly name, like web sites have. However most broadband services operate a DHCP IP addresses, which means that you address could change frequently. What you need is a Dynamic DNS service, that can be kept up to date with what you current IP address is . Even if your service provider keeps changing your IP address, you will have the same address all the time. Having a fixed name, instead dynamic number makes using services such as email services, remote access to your own machine and direct peer to peer chatting, such as with NetMeeting much easier. With the increasing popularity of broadband permanent internet connects, Dynamic DNS services have mushroomed in number (check the Google Directory listing linked below). What is DNS? DNS stands for Domain Name System. Think of it like a phone book. Every machine on the internet has a number like 81.27.96.35. You could browse the web this way, (try it) but you cannot know every number - there are thousands. Instead you can type in a more friendly name, in this case http://www.amset.co.uk/ . When you type in the name, your machine goes to already defined name servers, looks up the name and gets the IP address. If the local server doesn't know the address, then it passes the request to the next server in the chain. Once it has the address it can connect to that server and you are browsing the web. As long as you know the address of the name servers, then you can look up the address - in much the same way that you know 192 is directory enquires for the telephone. When you connect to the internet using a standard dial up modem in most cases you are given a dynamically assigned IP address. This changes each time you connect. With a cable modem or other permanent internet connection you are given an IP address in much the same way (unless you have paid for a fixed IP address) except you will typically have it for longer. However the address will change. This is where a Dynamic DNS service comes in. A more detailed, non technical explanation of domain names can be found on Internic's web site. (opens new window) What is a Dynamic DNS solution? Dynamic DNS allows you to keep another server informed of what your IP address is all the time. When it changes, the server has to be updated and then you can continue using it. It allows you to run services that need a fixed IP address, like mail servers. The updates can be carried out in two ways, either manually (you go to the web site and enter the IP address) or automatically using an agent. The automatic solution is best if you have a machine connected to the Internet permanently. If you address changes while you are away from the computer, then it is automatically updated. Choosing a Solution If you type Dynamic DNS in to search engine then you will find there are quite a few services available. Some you pay for, some you don't. A good place to start would be Google's directory: Keeping it Up to Date Once you are using a Dynamic DNS solution then you need to keep it up to date. This is carried out using an agent. This needs to be installed on a machine that is on all the time so that it can monitor your connection for any changes to the address. There are many agents available, some are free, some need to be paid for, depending on the complexity of the client. Check the site of the provider you have chosen for information on these agents. Working with a Domain Name With most Dynamic DNS service providers, you have two ways of using their service:
Depending on whether you have registered a domain name will depend on how which option you want to use. Email If you are using your own registered domain name, then things can look complicated. Web Domain Registration If you don't have a domain name, and would like to get register one to use with a Dynamic DNS service, then one that we have used with great success ishttp://www.wittyweb.net/ . Other Ideas Using with your LAN If you are on a LAN, then resolution of the Dynamic DNS name may not work or even give the wrong address. To resolve this, put a hosts file on each machine with the local network address instead. This page has more information on creating your hosts file. Links: Another Explanation of Dynamic DNS: http://www.technopagan.org/dynamic/ | ||
| Last Page Update: 03/11/2007 |
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