When your Mac is connected to a network, it is assigned an address on the network called an IP address. The IP address is four sets of digits separated by periods, with up to three digits per set. If the Mac is connected to a network as...
Method 1 of 4:
Finding Your Internal IP (OS X 10.5 and Newer)

Click on the Apple icon on the upper-left corner of the screen.

Scroll down and select System Preferences.

Click Network. This should be on the third row.
Select your connection. Typically you will be connected to the network via AirPort (wireless), or Ethernet (wired). The connection you are using will say Connected next to it. Your IP address will be listed directly beneath your connection status, in smaller print.Method 2 of 4:
Finding Your Internal IP (OS X 10.4)

Click on the Apple icon on the upper-left corner of the screen.

Scroll down and select System Preferences.

Click Network. This should be on the third row.

Select your connection. You can select the connection that you want the IP address for in the Show dropdown menu. If you have a wired connection, choose Built-In Ethernet. If you have a wireless connection, choose AirPort.

Click the TCP/IP tab. Your IP address will be listed in the settings window.[1]
Method 3 of 4:
Finding Your Internal IP Using the Terminal

Open the Terminal. This can be found in the Utilities section of your Application folder.
Use the ifconfig command. The normal ifconfig command will result in a lot of data displayed that is not necessary and a little confusing. The following command will remove most of the unnecessary stuff and display your internal IP address:ifconfig | grep "inet " | grep -v 127.0.0.1[2]

Copy your IP address. Your IP address will be displayed next to the 'inet' entry.
Method 4 of 4:
Finding Your External IP
Open your router's configuration page. Almost all routers can be accessed through a web interface where you can see and adjust settings. Open the web interface by entering the router's IP address into a web browser. Check your router's documentation for the specific address. The most common router addresses are:
Open your Router Status. The location of the external IP address will vary from router to router. Most have it listed in the Router Status or WAN (Wide Area Network) Status.[3]
Google search 'ip address'. The first result displayed will be your external, or public, IP address.
Update 04 March 2020
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