Internet, internet

When the term Internet refers to the global system of interconnected networks (such as the World Wide Web, newsgroups, chat rooms, and online forums), it is a proper noun and requires a capital:

• Information found on the Internet is not always reliable.
• This company is an Internet service provider.

When internet refers to a smaller-scale network connecting two or more networks via a bridge or a gateway, it is being used generically and does not take a capital, as in the following example:

• Install an internet or external router.