Monday, September 11, 2017

How to find IP Address from hostname in Windows Linux and Unix

IP Address from hostname in Windows and Linux
How many times in a day you have a hostname and you want to know the IP address? Hostname to IP address and IP address to hostname conversion is one of frequent thing which we need to do for many things when dealing with networking command in Unix. For one command we need an IP address for others we need hostname even from bash script sometimes we require a hostname and sometimes we look for IP address. networking commands are not as popular as find command or grep command but they are equally important and if you working in Windows or UNIX environment you must learn them and they should also be included in any list of Unix commands for beginners.

By the way, In this hostname to IP address tutorial, I will show you how to get the IP address from host name or computer name in Unix or Linux and how to get hostname if you have an IP address. If you are looking for a way to do it via Java program then you can also see my post on how to find the IP address of the localhost in Java.

By the way, if you are new to Linux then I also suggest you go through a comprehensive Linux course to learn some basics commands and fundamentals like Linux file system, permissions, and other basic things. 

If you need an online course, I highly recommend Linux Mastery: Master the Linux Command Line in 11.5 Hours on Udemy. It's a very practical and hands-on course to learn Linux fundamentals in a quick time. It's also very affordable and you can buy in just $10 on Udemy flash sales which happen every now and then. 


Finding IP address from hostname in UNIX and Linux

If you are working in a UNIX network and have lots of machines in LAN (Local Area Network),  many times you want to know the IP address of computers from the hostname. 

Here are the top 4 ways of getting an IP address from hostname in Linux or UNIX machine

1) IP address using hostname command in Unix/Linux


~/hostname -i

This is the easiest way of finding the IP address of your computer but the limitation is that sometimes this option may or may not available in your UNIX machine e.g. I hardly find this command on Solaris and IBM AIX machines but they are mostly available on Linux Servers. also, a limitation of the hostname is that you can not find the IP address of any other machine. It's like finding IP address of the localhost.



2) IP address using ping command in UNIX or Linux


stock_trader@system:~/test ping trading_system
Pinging trading_system.com [192.24.112.23] with 32 bytes of data:
Reply from 192.24.112.23: bytes=32 time<1ms TTL=128
Reply from 192.24.112.23: bytes=32 time<1ms TTL=128
Reply from 192.24.112.23: bytes=32 time<1ms TTL=128

ping is another simplest way of finding the IP address of localhost or any other host in network, if you know the hostname or computer-name just ping and it will display IP address associated with it. Normally pint command is used to check if a host is alive and connected with the network. 

In the above example, the IP address associated with trading_system is "192.24.112.23". The disadvantage of using ping command is that you can not convert IP address back to the hostname.



3) IP address using nslookup command in UNIX or Linux


stock_trader@system:~/test nslookup trading_system
Name:    trading_system.com
Address:  192.24.112.23

nslookup is my favorite command for getting IP address form hostname, its very powerful and also available in many UNIX operating systems like Linux, Solaris, IBM AIX, Ubuntu or BSD. Another advantage of the nslookup command is that we can get either from hostname to IP address or from IP address to hostname

It can also be used to find the IP address of your own host or any other machine in the network. In the above example of nslookup, we have displayed IP address associated with trading_system. If you want to find hostname from IP address you can just provide IP address instead of hostname


4) How to find the IP address using the ifconfig command


ifconfig is another networking utility in UNIX or Linux which can be used to find IP address of your UNIX machine. ifconfig shows a lot of information so I just grep on inet to find the IP address in the below example, IP address associate with "trading_system.com" is "192.24.112.23".

trading_system.com $ /sbin/ifconfig -a | grep inet
inet 192.24.112.23 netmask ffffff00 broadcast 192.24.112.255


How to find IP Address from hostname in Windows Linux and Unix


IP Address from hostname in Windows Linux and Unix

Now, let's see some examples to convert hostname to IP address in Windows, Linux, and other UNIX based systems. 


1. How to find the IP address of your computer in Windows

Surprisingly some of the above examples of finding IP address from hostname will work is windows ditto. You can use ping and nslookup in exactly the same way as shown above. Even hostname command is available in windows command prompt but I doubt about options "hostname -i". Another change is in command ifconfig , instead of  ifconfig windows uses  ipconfig  command to find out the IP address of your computer in windows.

How to use ipconfig command in windows to find IP address
Here is an example of using ipconfig command in windows to find out IP address of our computer:

C:\Documents and Settings\stock_trader>ipconfig
Windows IP Configuration
Ethernet adapter Local Area Connection:

        Connection-specific DNS Suffix  . : trading_system.com
        IP Address. . . . . . . . . . . . : 192.24.112.23
        Subnet Mask . . . . . . . . . . . : 255.255.255.0
        Default Gateway . . . . . . . . . : 192.24.112.254



2. How to find the external IP address of your network or computer

All the above examples will show your internal IP address if you are inside a LAN. If you have connected with the internet and want to know your external IP address assigned by your service provider there are lots of websites that will let you know your IP address e.g.  ipchicken.com just logging into this site and it will show you your IP address and location. If you have an IP address and wanted to know about the location you can also get it from the internet.

That’s it from me on these nice little tips of converting an IP address to a hostname and then back from hostname to IP address. Let me know if you have some other ways to find an IP address and hostname of the local machine and remote machine.

Enjoy

Further Learning
Linux Command Line Basics
Linux Command Line Interface (CLI) Fundamentals
Learn Linux in 5 Days and Level Up Your Career

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11 comments :

Javin @ String split Java said...

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heera said...

Thanks . I was looking for exact same information, command to find hostname from ip address. we have linux machines in our lan network and I just joined. this unix tips will surely help me lot.

unixman said...

hostname -i will not work to find IP address of another computer, it will only work for current host. I think only available option to get IP address of another computer is "nslookup"

Anonymous said...

how to check the loction of my friend while chatting.

please help me one of my friend told me he is in us but i think he is telling lie so please help me to guess from where he is calling .

send the answer at papadonpart2@gmail.com

Jimm said...

how to find IP address in Unix operating system which doesn't have nslookup command ? is there way to determine IP address without using nslookup

King said...

Thanks for this. i was looking for this "nslookup" command

Anonymous said...

Hello Javin, How will you convert an IP address to Hostname in Java? Can you please write about that? Thank you sir.

Samir said...

I am using linux system for my office work first time even though I have hosted all my website at linux hosting servers. There are few things I should have learned before like you let us know about ip host, pinging commands at linux system. I am a fast leaner yet I think it will take a month to get used to it as always typed wrong command and right click is something which we always used at windows.

Anonymous said...

You can also use 'host' command to display IP address associated with any DNS name (or hostname). It's a DNS lookup utility similar to nslookup but it doesn't print name of DNS server used to resolve addresses. In fact, host command output is much cleaner than nslookup, you will see something like this

host yahoo.com
yahoo.com has address 130,.40.23.19
yahoo.com has address 130,.40.23.29

It will print all IP address associated with a DNS name and registered in DNS server.

Anonymous said...

@Anonymous, indeed I would prefer host and nslookup any day than other commands, but you should aware that there is something called nscd which keeps a cache of most used queries on naming server. If a host got IP address change but still resolving to old IP address then this is one place you should check. Sometime name server can also be faulty.

Unknown said...

Mmmh nice...

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