VeriSign SiteFinder

Introduction & The Idea

A few people have commented and/or asked about what this is. To save me writing the same thing over and over again, here is some information. The information does exist elsewhere, but many misinterpret it, here's my attempt at a simplified version. VeriSign are a company who own Network Solutions, and who therefore manage the DNS(Domain Name System) tables for .net and .com domain names. They have tried to implement a system, by which when you make a typing error in a domain name, or enter a non existent domain name, they recommend some similar alternatives to what you typed.

DNS Tables
To help understand, I will explain simply DNS tables.
When you make a new friend, one thing you probably do is take their name and phone number. But how do you remember this person? Well, you remember their name, it has meaning, and when you want their phone number, you look it up. There is no logical mapping between a person's name and their phone number, it's almost random.
Websites & servers are located by an IP address. But you get to them by typing their "domain name".
DNS tables are the phonebook of the internet. When you make a request for http://www.helpbytes.co.uk a DNS server maps that domain name to the IP of this server so it can be found.
VeriSign manage the DNS table for .net and .com domain names. When you make a request for a .com or .net domain name, the mapping/looking up is done through their servers.

What are they doing? How?

Usually, if you type a domain name that doesn't exist, it cannot be "resolved" and your browser would simply show the appropriate error message.
What VeriSign are doing is mapping/resolving domain names without an entry to their own servers. On this server is a system which spellchecks the domain name against other domain names in their servers, and outputs appropriate matches. Your browser at this point is in a state such is just thinks its the webpage you asked for, and you get returned these search results.
It's similar to the MSN search that takes place in Internet Explorer when it can't do anything with the domain name you entered, but that is an optional add-on controlled by Internet Explorer. VeriSign SiteFinder is controlled remotely on the important DNS servers.

Applying that to the telephone numbers

Lets get back to the telephone number idea again. You have a friend, but no phone number for him. You call the operator. You ask for "Jon Tomson's" number, the operator tells you that he person doesn't have a telephone.
If VeriSign owned the operator, they would tell you they don't have a phone, but would suggest you call "John Tomson" or "Jon Thomson" instead, because they are similar.

Graphical Example

The following image shows what's happening, where, and how.
Some Terms
N/S: Name Server.
TLD: Top Level Domain.
ISP: Internet Service Provider.
A..M: There are 13 root servers around the world, named A to M.

Great, what's the problem?

What's the problem, here are a few:
1. How many times do websites close you regularly visit? You type the domain, nothing comes back, you presume it's closed, you don't visit it again?
Now imagine making a mistake in the domain name. You get this search page, you don't realise you made a typo, you just presume the domain name doesn't exist anymore, and you lose interest in that site.
2. It takes much longer for the search page to show than a plain error message.
3. There is nothing to stop VeriSign logging visits to their page, putting up adverts, setting cookies for 3rd parties, and other things similar. Your privacy may be infringed, but because this is automatic, you can't stop it, not even if you don't agree with the privacy policy.
4. Domain names are not just used for websites, they are used for e-mails! If you accidently type the domain name wrong when sending an e-mail, who receives the e-mail? VeriSign do! Testing has shown at present they reject the e-mail after they receive the recipient, but they can still log the fact your e-mail is active and tried to send e-mails to a domain name. They could log and sell your e-mail address!

Conclusion

In conclusion, it looks like a great system, can auto correct typos in your domain name, and show similar results. But it's automatic, you can't turn it off, and it's out of everyone's control. There is a possibility for your privacy to be compromised.

Blocking It

Due to the fact it works at the DNS end of things, it would be undectable you was receiving a response from the wrong place, this is because the IP lookup and the IP sending the info are the same. BUT to make your browser see the verisign URL, it uses a HTTP redirect, meaning your browser has to make a request of its own to the verisign site. You can block this site on your firewall, current IP is 12.158.80.10, remote port 80.
Because it works in this manner, an ISP could block this service too.

Links

VeriSign
Network Solutions
Site Finder