To start, there are internal and external IP addresses. Your internal IP address is the one that other computers can use on your local area network (LAN) to locate your machine. Your external IP address is the one that you use to contact external websites on the internet.
Internal IP Address Ranges
There three ranges for internal websites:
10.0.0.0 to 10.255.255.255 – Class A
172.16.0.0 to 172.31.255.255 – Class B
192.168.0.0 to 192.168.255.255 – Class C
Internal IP addresses are always in one of these ranges. That is one way to tell if it is an internal or external IP address. Note that the first range fixes the first eight bits. The second fixes the first 12 bits. Finally, the third fixes the first 16 bits. That explains why the ranges are what they are.
To find your internal IP address, open a command prompt and type ipconfig, as shown below.
Notice that the internal IP address (IPv4), of this computer, is 192.168.1.5.
External IP Address
Your external IP address can be determined by any website to which you connect.
This is a general fix for any NuGet package that can not be found. Open the Options dialog by selecting Tool->NuGet Package Manager->Package Manager Settings. This is will open the dialog shown below. Select NuGet Package Manager->Package Sources as shown:
Click the Plus Button to select a new source. Fill in the name as Nuget and the Source: as https://api.nuget.org/v3/index.json and click Update and OK.
You might still need to set the package source. Right Click Dependencies->Packages in the Solution Explorer and select Manage NuGet Packages… to open the NuGet Package Manager Pane.
Now, just select NuGet as the Package source: as shown above and that should fix it.