A primitive and simplistic example of a host offering protection might go something like this:
They have a fat (gigabit) connection to the Internet, not some residential "spare server sitting on my desk" setup.
You have an account with them, they give you a DNS address (myneatserver.com) that points to their routers. They give your specific server an internal IP address, let's assume something like 10.1.1.1
You start getting bombarded at myneatserver.com from someplace in Saskatchewan. The host then changes your internal IP to 10.1.1.2 and diverts traffic originating from Saskatchewan to your DNS somewhere else. For the rest of the Internet, your server is still up. For that angry rage-troll in Saskatchewan, they aren't able to affect you. They are still sending a flood of data, but your host is filtering it out for you.
Still, this isn't something significant to worry about at this point. I just brought it up because it is a point of attack for all applications that require authentication.
They have a fat (gigabit) connection to the Internet, not some residential "spare server sitting on my desk" setup.
You have an account with them, they give you a DNS address (myneatserver.com) that points to their routers. They give your specific server an internal IP address, let's assume something like 10.1.1.1
You start getting bombarded at myneatserver.com from someplace in Saskatchewan. The host then changes your internal IP to 10.1.1.2 and diverts traffic originating from Saskatchewan to your DNS somewhere else. For the rest of the Internet, your server is still up. For that angry rage-troll in Saskatchewan, they aren't able to affect you. They are still sending a flood of data, but your host is filtering it out for you.
Still, this isn't something significant to worry about at this point. I just brought it up because it is a point of attack for all applications that require authentication.