DNS Resolution
What is DNS?
Every computer connected to the Internet is identified by a unique address known as the IP address (Internet Protocol address). The IP address is a 32 bit binary number, which for ease is usually expressed as four sets of decimal numbers, each representing eight bits, separated by a period e.g. 206.43.44.130.
The purpose of using DNS is to make navigation around the Internet easier by replacing an IP address with a tangible name. For example, it is much easier to recall a 'name' like 'activeconcepts.com' than an IP address of 206.43.44.130.
'DNS' is simply the abbreviation for Domain Naming Service. A DNS server is just a computer running special DNS software.
The DNS software is made up of two separate pieces of software - the actual name server and a 'resolver.' The DNS software itself replies to a request from a browser by supplying the conversion from IP address to the name.
If the initial DNS server does not have the conversion details, it passes the request to its resolver, which then passes the request on to another DNS server and so on. Unfortunately, not all IP addresses can be given a 'name.'
When you type a web site address into your browser, the request is passed to the closest DNS server (usually maintained at your ISP). If that DNS server has previously been asked for the same information, it will be holding the details in its cache (temporary memory) and will provide those details back to your browser.
If it does not hold that information in its cache (or the cache has been cleared to prevent outdated information from being passed on) the resolver will pass the request to another DNS server further up the tree.
This process continues until a name server is located that does have the details (then known as an authoritative server) and the information is passed back down the tree to your browser. The beauty of this method is that any DNS servers in the tree that handled your request are provided with the information. Therefore, all DNS servers on the Internet are continually updated with the most current information.
Prior to the introduction of the DNS system, all domain name information was held in a central system that was manually updated. The administrators of the DNS server would then need to copy the latest information to their own servers on a regular basis. As the Internet grew, this method became cumbersome.
Since the DNS system is a distributed database of information that resides on many different DNS servers around the world and there is no single entity responsible for its updating, the DNS system offers basically unlimited growth potential.
What does it mean for my web analysis?
When you are using a web site analysis tool such as Funnel Web, you want to get as much information about your web site traffic as possible. Since the web server log only records the IP address of the requesting computer, a straightforward analysis will only provide you with the visit details against an IP address.
Unless you have a photographic memory, any reports showing only IP address
will be pretty meaningless. The Funnel Web graph below shows how some but
not all IP addresses can be changed into domain names.
You can select within Funnel Web to resolve the IP addresses into the
appropriate domain names. Then your reports will actually contain meaningful
domain information. When performing DNS 'lookups,' your analysis program
connects to the Internet and request the current domain name information from
the DNS servers in the same way a request from a browser is processed.
To ensure you get the maximum information from your reports, you should always select for the program to do an online DNS resolution. If your log files are large, this process could add significant time to your report processing.
Most packages like Funnel Web actually generate their own DNS cache in the same way a normal DNS server does. This enables your analysis package to refer to its cache for the domain name information without losing performance.
In some cases it is not possible for a program such as Funnel Web to fully identify the domain name information. This may occur for a number of reasons:
- The ISP responsible for maintaining the name listing fails to correctly maintain the records.
- The DNS system cannot be contacted due to server errors or lack of Internet connection.
- You have disabled the DSN 'lookup' feature in your analysis software to save time.
Summary tips for Funnel Web users:
- Use the DNS cache option wherever possible. Clear your cache or run reports on a regular basis with the DNS 'lookup' turned on. This will ensure that your DNS cache is holding the most recent information.
- If you are not interested in the domain name details for your reports and require maximum processing speed, select DNS lookups = OFF
- For maximum accuracy of your domain name information, select DNS Lookups = ON.
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