-: Domain names and IP ranges.
So we talked about DNS harvesting a little bit
in the last lecture.
We're gonna talk a little more
of the overview of the DNS system
just to make sure we really sink this home.
So domain names are the human readable names
like jasondion.com because humans remember names
better than we remember numbers.
So if I had to give you my IP address
and said hey come visit me at 66.123.45.2,
that's not really memorable.
But jasondion.com is a lot easier for you
to remember.
Or cisco.com or google.com, right?
So to get that name, you have to buy it
through a registrar.
And the registrars are the ones who manage
this whole DNS system.
There are a couple of top name domains
like .com, .net, .org, .edu, .mil
and .gov here in the US.
Now outside the US, there are also country code ones
like .com.uk or .co.uk, .edu.it
because they add that country code at the end
which is known as a country code
top level domain.
Now, most companies, even if they're outside the US,
try to get that .com itself because
that carries a little more weight in the search engines
necessarily than some of the other country codes
or some of like the .biz or other ones like that.
Now, when you look at the IP ranges.
If I wanted to have IP ranges assigned to me,
I need to get them from one of the regional authorities.
And there are five regional authorities.
There's the one in Africa called AFRINIC.
There's ARIN which is for US, Canada, Antarctica
and the Caribbean.
There's APNIC, which is Asia, Australia,
New Zealand and other countries in that Asia area.
There's LACNIC which is for Latin America
and other parts of the Caribbean
that aren't covered by ARIN.
And then there's RIPE, which is Europe, Russia
and the Middle East.
Now each authority has their own Whois servcies
for their IP space.
So if you're trying to do DNS harvesting
and you're trying to find information
about jasondion.com and you look at it under AFRINIC,
you're not gonna find the information you're looking for.
Because my registrar was through ARIN
because I'm a US based company, right?
So that's the idea here,
is you gotta figure out which region
that company or that IP block belongs to
if you're gonna look up who owns that IP range.
Now looking up the domain name,
you can do that with any Whois platform
because all five talk to each other.
But when you try to go in for an IP range itself,
like if I said who owns 8.8.8.8,
you've gotta find out who owns that
first regionally, which in this case is ARIN
because it's a US company, it's Google.
You can then look up 8.8.8.8
and find out that there is a block
of IPs owned by Google, including that one.