From time to time I run across things on the Internet that are handy, and I like to pass them along to my readers.
If you have a concern about the content that Web surfers can see on your computers, read on.
This column will help you to filter out stuff that you consider is undesirable.
Now, I don't want to get into the role of being an Internet censor. I won't judge what's good or bad for people to look at. That's for you to decide. I will, however, give you the means to block content that you've decided is not appropriate.
You can use the service of an organization called OpenDNS to do this. It offers a free service, and a paid service with more features.
Some of this material will necessarily be technical. Implementation will require some level of technical prowess, although it's certainly not rocket science.
To start off, I need to explain a little about how surfing the Internet works.
When you type www.thedailystar.com into your Web browser, your computer connects to The Daily Star's website and displays what's there. But how does it do that?
The Internet works using numbers. Every computer that's connected to the Internet has what's called an Internet Protocol address, or IP address for short. That address takes the form of a number, and each computer is different.
For example, The Daily Star's website IP address is: 188.8.131.52. But who wants to try to remember a lot of numbers? Nobody I know. So the Internet uses what's called the Domain Name System.
This system lets you type a name into your browser instead of an IP address. It's a lot easier on the memory. You can much more easily remember the domain name "thedailystar.com" than an IP address.
For this to work, there are computers known as domain name servers, or DNS servers, on the Internet. These computers maintain a constantly evolving list of domain names and corresponding IP addresses. When your computer wants to go to thedailystar.com, and it doesn't know the right IP address, it will query a DNS server to find it. Once it has the address, it can interact with the website.
If it can't find the IP address, it won't be able to get to the site. Usually, your Internet provider operates a DNS server for your computer to work with.
So, what we do to implement this filtering service is place a filter between your computer and its ability to find out a domain's IP address. This is essentially what OpenDNS does. You use the DNS servers at OpenDNS instead of your Internet service provider's DNS server. In general, here is what you do.
Go to www.opendns.com. Read over the information, and sign up and create an account. The technical details of what will have to be changed will be different depending on how your computer and/or your network are set up, but there is quite a bit of instructional help on the site.
If you have a hardware router, which is highly desirable, it's best to set that up to use OpenDNS's DNS servers, that way all the computers on your network will be involved in the filtering.
If you only have one computer connected directly to the Internet, you can change the settings on that to use OpenDNS instead.
Most individuals will have what's known as a dynamic IP address provided by your Internet service provider, and will have to install a piece of software from OpenDNS that will identify your computer or network to them. It has to know who you are so it can filter websites the way you want.
Yes, I said the way you want. You log in to the OpenDNS site with your account credentials, select your own network, and you can select the types of sites that are to be blocked or allowed. The selection process is straightforward and comprehensive.
There are other benefits and features of this service, one being its speed and reliability, but you'll have to go to the site for yourself and decide what's for you.
I should note that although this system of filtering will keep honest people honest, it's not truly a bulletproof solution. If a user is knowledgeable, determined and has the required access rights, he can find a way around it.
If you're in a situation where you need absolute dependability, you will need to research a more hardcore (excuse the pun) filtering system, and maybe spend a significant amount of money on it.
If, however, you're not in that category, OpenDNS may be a good solution for you, and now you know about it.
Bruce Endries is former systems manager at The Daily Star. He can be reached by e-mail at email@example.com. His columns can be found at www.thedailystar.com/techgp.