Understanding Technology
Why is a Reverse Lookup Important?
All of us visit web sites by typically entering or clicking on a web address (i.e. the URL for the given web
site to retrieve the associated web pages). But web-based information is eventually retrieved via the
associated Internet Protocol (IP) address. In other words, we enter the web address into the browser, a Lookup
is performed by domain name servers, the IP address is retrieved, and then the associated web site is retrieved.
While this is the accepted process for most Internet users, there is another important aspect of web hosting
that is often overlooked: Reverse (DNS) Lookups.
To better understand what I am talking about, we need to visit a publicly accessible web site that provides many
different Internet functions: http://www.DNSStuff.com. As
you view this web site (you will notice many different techie-looking forms on the screen) let's first focus on
the top right-hand-side at the DNS Lookup.
Let's enter "InfoAge.US" (my company's primary web address) into this form and then click
"Lookup." What you
should notice on the responding screen we see the coresponding IP address returned:
204.14.80.225. The
return of a corresponding IP address is normal and expected, but to continue our example, please return to the
initial DNS Stuff web page.
Look for the small form on the 2nd row, center position titled Reverse DNS Lookup, and then enter
the previously retrieved IP address from "InfoAge.US" which was: 204.14.80.225
. When you click on "RevDNS"
(to retrieve the associated Reverse Lookup address) you will see that the Answer is
InfoAge.US.
OK, before we go farther into this topic, please understand 4 things: (1) IP addresses having a forward address
are supposed to have a corresponding Reverse (Lookup) address; (2) many Internet services (search engine
placements for example) are strengthened when Reverse addresses are deployed correctly; (3) many web sites do
not have Reverse addresses; and (4) many web sites have Reverse addresses that do not correspond to the
forward address.
For example's sake, here are five web sites that (as of today) are lacking Reverse Lookup addresses or have
Reverse Lookup addresses that do not match their (forward) web address:
There are several reasons why an IP address would be lacking a Reverse Lookup address or may have a non-matching
Reverse Lookup address. The IP address may be used to host many different web sites (small web companies do this
to save money); the DNS servers may be mis-configured; the IP addresses may be in transition; the
Internet provider may not understand how to configure Reverse Lookup addresses; or the web developer may be
inexperienced.
At The Information Age, Inc., we use a single, distinct IP address for every one of the web sites that we
host. Additionally, we work hard to make sure we have the correct Reverse Lookup address in place for the web
sites that we manage. What follows are example links to the Reverse Lookup reports from six of our managed web
sites:
You may notice from the listed examples that there are several very similar web addresses that have different
IP addresses, but they return the correctly configured Reverse Lookup address. As mentioned during last week's
article, (at The Information Age, Inc.) we own our IP addresses, but we also operate our own Domain Name
Servers. In other words, we control our service delivery environment wich is necessary in the
competitive Internet service business.
In conclusion, there are 2 rules that your organization should take away from today's article. It is better
for your web site to have its own IP address (verses sharing it with many other web sites/addresses);
and it is important for your (dedicated) IP address to have a correctly configured Reverse Lookup record
in place. You should demand these from your Internet service provider or your web hosting company.
To learn more about the Reverse Lookup standard (i.e. RFC 1912), simply click here.
Until next time, we’ll see you in The Village!
In the event you do not see what
you are looking for on this page, or anywhere else in this portal web site, please enter the information you are looking for into the
Google Search field at the top of any of our pages and then click on Google Search.
Want to Learn How to Search Better?
To take advantage of one or more of
The Information Age, Inc.'s online advertising opportunities (Display Advertising,
Directory Listings, or Classifieds), simply send an email message to
Sales@InfoAge.US, or pick up your phone and call our sales organization
(770-838-0373).
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