Can someone explain what this is? Why would I need it? What do I do if it doesn’t work for me?
I have 10mbps download now, would this make my PC downloads & streaming any faster?
Lots of questions, I know, but I just heard about OpenDNS and thinking of trying it.
Thanks
No.
Edit: Sorry, hit post too soon. Are you having problems with the DNS provided by your ISP?
DNS provides name to ip address resolution, allowing you to use a friendly name like straightdope.com. This is usually provided by your isp. Some people do not like the features, reliability or trustworthyness of their isp, and prefer to use a known quality. Google provide a trusted public DNS, but do collect useage information from this service. OpenDNS does the same, with a variety of features like DNS filtering. OpenDNS will redirect unresolved names to an ad supported search page - this is how they make money.
OpenDNS may provide better DNS than your isp, or you may just like the features.
DNS is Domain Name System.
Here’s the wikipedia page about it:
Basically, computer names like boards.straightdope.com are meaningless to a computer. The computer needs to convert that into numbers (an IP address) that it can use. To do this, the computer first starts with itself, looking in your local etc/hosts file to see if you have an entry that matches that name to an IP address. If there isn’t an entry for it there (which there usually isn’t these days) then it sends a request to whatever IP address is configured as the DNS server for your system. That computer is typically run by your ISP. If it doesn’t have an entry for it, then it sends a request up to a higher ranking DNS server, and if that one doesn’t have an entry for it it also sends it further up the chain. If the request keeps getting passed up the chain you’ll eventually reach one of the root DNS servers of the entire internet, of which there are only 13, and they all have their own copy of the DNS “master list”. Usually one of the lower ranking DNS servers will have an entry, so it is fairly rare that the request goes all the way up to one of the root servers. Somewhere along the way, though, your request (something human readable like baords.straightdope.com) is going to get converted into an IP address (209.104.5.198 when I tried it just now) which is what the computer uses to fetch your web page.
Typically, your computer’s IP address and DNS server are configured using what is called DHCP. Your computer sends a request out and gets an answer from your ISP’s DHCP server, which gives your computer an IP address and one or more IP addresses to use as your DNS server (usually there’s a backup in case the first one fails).
OpenDNS is more than just one thing. For business users, they sell software that you can use to set up your own local DNS server. That way most oft he DNS requests in your business go to your own local server and don’t go out on the internet (which is faster). That costs a lot of money. For home users, they seem to provide an alternate DNS server that you can use instead of your ISP’s DNS server. This probably isn’t going to be any faster than your ISP’s DNS server, and in fact will probably be a bit slower since the DNS request has to be sent further across the internet. The speed difference probably won’t be noticable. OpenDNS, according to their web site, does claim to fix common typos in domain names and does some sort of filtering to block own known malicious sites. I’ve never used them so I can’t say how well this works or how effective it is to protect your computer.
When you go to the OpenDNS web site and click on home solutions it takes you to a page that says “Premium DNS Make my Internet faster and more reliable.” While their filtering may have some benefit towards reliability, I’m not seeing how they could possibly make your internet noticeably faster. DNS requests to your ISP are usually handled pretty darn quickly. The things that affect your speeds are usually things like how choked your local ISP’s network is, how fast and busy the remote server you are trying to contact is, and any bottlenecks in the network between here and there. DNS speeds rarely factor into it. Seems like a bit of false advertising to me, though worded so vaguely that you can’t actually call them out for lying.
Thanks, All!
I currently have no problems with my ISP, so I think I’ll stick with it.
I *really *appreciate your answers. 
I stopped using OpenDNS a while back because their filtering was too intrusive. It is supposed to be possible to bypass the filters but it is not a simple “Click. It’s off.” and I wasn’t willing to spend the time to learn their unintuitive system.