Maybe there was a time, in the distant-past, when it was okay to plug your broadband modem (cable or DSL or fiber or satellite, whatever you’ve got) directly into your computer. Maybe. But doing that today is tantamount to leaving your front door wide open for malicious jerks to deposit trash in your foyer while stealing your hard-earned cash.
There should always be something between you and your broadband for protection: a router. Here’s why you need one for safety, plus all the other benefits a router provides.