Below we will see some useful networking commands that are pre-installed on your computer and will help you to know everything about a website.
What is my IP address? Who is the host of a website? Which mail service uses this domain? There are tools on the web that can reveal these details, but this can be done using the command line on your computer (Linux-Mac).
What is my IP address?
Make a request with curl or wget at checkip.amazonaws.com and you will see the public IP address of your computer. You can also open the page whatismyip.akamai.com of Akamai and you'll see your external IP address.
What is my private IP address?
ifconfig en0 | grep inet
Your computer has a private IP address that only works on the local network.
Find the location of the IP address
The free ip2c service can display the country of an IP address.
Alternatively, use the ipapi service to get more details of an IP address (City name, time zone, and even latitude - longitude associated with an IP address.
Check DNS records
The dig command will help you request any type of DNS records for a domain from the command line.
1. Find the IP address of a website
dig + short iguru.gr
2. Find the domain mail server
The mail exchange (MX) records indicate incoming mail servers used to deliver email messages sent from a domain.
host -t MX iguru.gr
3. Display all the DNS records of a domain
See a list of all the DNS records of a domain, along with the TXT, MX, and other registrations.
dig + nocmd amazon.com any + noall + answer
Making a host page?
Use the dig command to find the IP address of a site, and then use the same dig command to perform a reverse lookup to find the host of that IP address.
For example, this command will display the IP address of Netflix:
dig + short netflix.com A | tail -1
Use the IP address of the next command to view the host name:
dig + nocmd -x 220.127.116.11 + noall + answer
Find the site owner
Use the whois command to reveal important information about any domain. You will see the date on which it was first registered, the contact details of the website owner, the expiration date of the domain, the name of the registrar and more.
You can also query for recording details of a domain server of a particular register with the flag -h. For example, the following command does a whois lookup on a site using the Google Domains WHOIS server.
whois -h whois.google.com domain.com
Ping network connectivity test
The ping command helps you control if a remote server is accessible and if your machine can connect to it properly.
ping -c 5 -i 2 iguru.gr
The above command pings the server 5 times with a wait of 2 seconds between pings.
Where is the mistake?
If your Internet connection is working, but you can not open a website can be a problem with an intermediate router that does not allow to pass the packets to reach the server.
The traceroute command will show you the way from your local computer to the site from which the traffic must pass. This information can be useful in diagnosing connectivity issues.