What is the domain name of an IP address?

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How does DNS work?
What is DNS lookup used for?
Overview of the forward DNS lookup process
How to perform a DNS lookup

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We were contacted by our ISP saying that one of our servers was issuing an attack on another computer.

May 23 14:11:35 wdc lfd[14308]: *Port Scan* detected from ***.***.***.*** (US/United States/-). 11 hits in the last 245 seconds - *Blocked in csf* for 3600 secs [PS_LIMIT]

I don't know what it means, but our server is a factory image, with only a couple programs running.

I would like to know the domain, but don't know how to look it up.

A domain name is an address on the Internet which people can use to find resources like websites, or send email.

For example - auda.org.au is a domain name which points to auDA's website.

Using domain names means we don't have to have to remember Internet Protocol (IP) Addresses. Every device connected to the internet - such as a server which hosts a website - has an IP address. which is a long strong of numbers and characters e.g. 2606:4700::6811:ed6b

The Domain Name System (DNS) matches domain names to IP addresses. When you type in a domain name into your web browser, it sends a request to a server (or a number of servers) for the IP address of the website you're trying to view, which then allows your browser to load it.

The process is similar when you send an email. When you push 'send' on an email, a request is sent to an email server, which then, based on the domain name in the recipient's email address, finds the IP address for the mail server for that domain name. That server, then forwards the email to the recipient.

Category: Registering a name

In this lesson you will develop an understanding of the learning strand Communication & Networks on your progress ladder, working towards yellow level.

What is a domain name and why we use them
What are IP addresses and why we use them
What is DNS and how it works and uses both domain names and IP addresses.

Look at your browser's address bar. What ever is written there is the URL of the page you are on. What ever is written there after the http://www but before the first / is the domain name of the site you are on.

You'll be very familiar with some domain names like;

google.com facebook.com yahoo.com youtube.com wikipedia.org

There are lots of Top Level Domains available to website owners.
.com, .org, and .co.uk are just some of a few.
Gather a list of 10 other Top Level Domains that are available.

Explain what a Top Level Domain is and give some examples for your notes.

Domain names are a little like addresses. For instance, the Prime Minister lives at:

10 Downing Street London, SW1A 2AA

This is nice and easy for humans to say and remember.
Another way of saying where the Prime Minister lives would be to use Longitude and Latitude.

51° 30′ 12.23″ N, 0° 7′ 39.5″ W

This is tricky for a human to remember but great for a computer.

Domain names are like address, they are designed for humans to read and remember. In reality a computer's address (that allows other computers on a network or the internet to find it), is made up of numbers.
Computer use IP addresses to send messages to each other.
Your Computer's current IP address should be shown below
We need domain names because IP addresses are too difficult for humans to remember.
Imagine typing in this every time you needed to go to a certain web address. Try the following in your home browser and see where each of the IP addresses takes you to. Note: those will not work inside school as accessing websites by IP addresses are blocked.

http://216.58.198.163

Try these as well at home and note the corresponding domains:

1. http://212.58.244.23 2. http://10.0.77.186 3. http://91.198.174.192

Answer the following questions in your notes.
- What is a domain name?
- What is an IP address?
- Why do humans not use IP addresses?

You can use the following animated tutorail to help you understand how DNS work

Imagine you had to explain DNS to somebody who had no idea what it was.
Using whatever software you like (or even pen and paper if you prefer), create a product that you could use to help explain DNS to someone. You could create a poster, a presentation, a report, an illustrated art work. It's really up to you.
You'll be awarded a bronze, silver or gold badge, depending on your teacher's assessment of your understanding of DNS.

Use the DNS lookup tool to find the IP address of any domain name. The lookup results will include the IP addresses in the DNS records received from the name servers.

How does DNS work?

The domain name system, otherwise known as DNS, is a key component of the Internet. DNS is the resolution of a domain name to an IP address.

Typical DNS queries are sent through four different server types: the DNS recursor, the root nameserver, the TLD nameserver, and the authoritative nameserver. The domain name system recursor gets the query and communicates with other domain name system servers in order to get the correct IP address.

Once it’s located, the domain name system recursor will send the query to the three other domain name system servers. Next, the root server, designated as the Internet’s domain name system root zone, responds to requests sent in the root zone. A list of authoritative nameservers that correspond with TLDs gets sent back as a response.

The TLD nameserver will then store the second-level domain IP address and release the website’s IP address. The query gets sent to the domain’s nameserver, and finally, the authoritative nameserver can respond to the original domain name system query.

What is DNS lookup used for?

DNS record lookups are used for translating IP addresses and domain names. With the tool, users can find the IP address of a domain name and other information related to domains.

Users can also perform a reverse DNS lookup, which uses pointer records to query an IP address in order to find a hostname. Note that some IP addresses will not return a domain name if there are multiple domains associated with a given IP address.

Overview of the forward DNS lookup process

The forward lookup, or simple DNS lookup, is the most commonly used approach to DNS. The forward approach to DNS is simply finding out the IP address of a domain.

People tend to find it difficult to remember long strings of numbers. Instead, it's easier to remember a domain name that uses words, like 'google.com' rather than '8.8.4.4.'

However, electronic devices use streams of 1s and 0s to communicate. The only way for one computer to communicate with another is by unique identification. The method of identification used on the Internet is IP addresses.

Here are the simple steps for DNS resolution:

A user enters a domain name into their Internet browser, like www.whatismyip.com.
The computer sends the domain name as a DNS request to the user's Internet Service Provider (ISP).
The ISP determines if it has the IP address associated with that name.
If it does not, the ISP forwards the request to other providers in an effort to locate the DNS record that contains the data.
Once the record is found, the IP address of the domain is returned to the user.
Now, the user's computer can communicate directly with the server.

How to perform a DNS lookup

To use the DNS lookup command, enter the domain URL into the tool above and select Lookup or press Enter. It will return the IPv4 address records for a domain.

You can also use the nslookup command to retrieve the nameserver type associated with a given domain rather than using the DNS lookup command.

If you're using a Windows computer, go to Start, then Run, and type command to open the command prompt. Type nslookup and hit Enter. Your search will bring back information about your local DNS default server and IP address.

If you're using a Mac computer, go to the Finder menu in the upper right corner and click Go. Find Utilities, then select Terminal. In the box that pops up, type nslookup followed by the IP address or domain you want to query, and then hit Enter. Your search will return the DNS server and IP address of the information you entered.