The following are the IP utilities available in Windows that help in finding out the information about IP Hosts and domains. These are the basic IP commands that every beginner in the field of hacking must know!
Please note that the the term Host used in this article may also be assumed as a Website for simple understanding purpose.

1. PING

PING is a simple application (command) used to determine whether a host is online and available. PING command sends one or more ICMP “Echo message” to a specified host requesting a reply. The receiver (Target Host) responds to this ICMP “Echo message” and returns it back to the sender. This confirms that the host is online and available. Otherwise the host is said to be unavailable.
Syntax: C:\>ping gohacking.com

2. TELNET

Telnet command is used to connect to a desired host on a specified port number. Just like a house having several doors, a host or a server has different ports running different services. For example port 80 runs HTTP, port 23 runs TELNET while port 25 SMTP. Like this there are several ports on a server through which it is possible for a remote client to establish a connection.
For a connection to be established, the port has to be open. For example, in the following command, we are trying to establish a connection with the Yahoo server on port 25.:
Syntax: C:\>telnet yahoo.com 25
C:\>telnet yahoo.com
The default port number is 23. When the port number is not specified the default number is assumed.
NOTE: If you are using Vista or Windows 7, Telnet feature may not be available by default. To enable it, you can refer my other post: How to enable Telnet feature in Vista and Windows 7?.

3. NSLOOKUP

Many times, we think about finding out the IP address of a given site. Say for example google.com, yahoo.com, microsoft.com etc. But how to do this? There are several websites out there that can be used to find out the IP address of any given website. However, in the Windows operating itself, we have an inbuilt tool to do this job for us. It is called “nslookup”.
This tool can be used for resolving a given domain name into its IP address (determine the IP of a given site name). Not only this, it can also be used for reverse IP lookup. That is, if the IP address is given it determines the corresponding domain name for that IP address.
Syntax: C:\>nslookup google.com

4. NETSTAT

The netstat command can be used to display the current TCP/IP network connections. For example, the following “netstat” command displays all the currently established connections and their corresponding listening port numbers on your computer.
Syntax: C:\>netstat -a
Type “Ctrl+Z” to exit.
This command can be used to determine the IP address/Host names of all the applications connected to your computer. If a hacker is connected to your system even the hacker’s IP is displayed. So, the “netstat” command can be used to get an idea of all the active connections of a given system.
NOTE: In order to obtain help on any given command such as its syntax, attributes etc., just type the “command-name /?” to obtain usage details on it. For example, to obtain help on “netstat” command just type: netstat /? and hit enter.