Firewalls and Protocol

Another way firewalls restrict access is by using protocols. A protocol is a means by which machines communicate. For instance, the letters "http" in a web address stand for Hypertext Transfer Protocol. Certain protocols are more secure than others, and some are used frequently by a human to communicate with a remote machine. These protocols are the ones misused by hackers, so some personal firewalls simply restrict the number of protocols to those less likely to be used by a hacker.