Discussion on:

How to find IP addresses and use them in Linux

To all who are interested in this sort of thing, Google now does this. Simply type "what is my ip" into the search and see what you get back.

however, I sincerely doubt many people will need to go about doing what you say and further doubt they'll get much use from doing so. The reason being, unless the US ISPs work a LOT different to those in Australia, every time your modem router has to be reset for any reason your public IP address is very likely to change because the ISP will assign you a new one from its group of IP addresses when you reconnect. Also, a good router will handle all this for you as part of its Network Address Translation (NAT) process and doing it in an invisible seamless manner. I see no real reason to send out your IP address as soon as you boot the system. If you need to connect to another system for the reasons stated, simply activating the appropriate application will see the connection established as and when needed. I see no point in doing that until you want it.

One of the reasons why one should track their IP address is perhaps dynamic DNS. It might be easier to get a generic dynamic DNS name associated with your IP so you can run your FTP SSH http server without having to worry about your IP changing all the time. With a bit of scripting or with a router that supports Dynamic DNS and doesn't forget to update it whenever the ADSL/Cable modem
loses its settings (like mine does) Dynamic DNS can work miracles.

There are lots of sites that can get your IP and spit it back...www.whatismyip.com
isn't the cleanest one of all ... try checkip.dyndns.org with the following
command:

curl -X GET http://checkip.dyndns.org

You'll get the following:
Current IP Address: x.x.x.x (Where x represents each number of your
external Ip address. All this is wrapped in http and body tags but the tags will dissapear once I paste them here)

For local IP addresses check this out:

ip -f inet addr

will give you the local IP addresses for your nic and localhost in the following format:

1: lo: mtu 16436 qdisc noqueue state UNKNOWN
inet 127.0.0.1/8 scope host lo
2: eth0: mtu 1500 qdisc cbq state UP qlen 1000
inet 192.168.0.10/24 brd 192.168.0.255 scope global eth0

then there's the old standby: ifconfig eth0

But for some distributions this requires higher privileges (ie root)

Also look at your distribution's repositories for a Dynamic DNS client that can update your Dynamic DNS Settings every time they detect a change in the external IP address

Hope this helps

There are two types of ip addresses in the computer. 1. Private or internal ip address and 2. Public or external ip address.
To find an internal ip address in Linux type ifconfig in the terminal and press enter then it shows the ip address,localhost etc..
To find an external ip address visit the site http://www.ip-details.com.