A ﬁrewall is a software program or hardware device that protects networks from unauthorized data by blocking unsolicited traffic. Firewalls allow incoming or outgoing that has speciﬁcally been permitted by a system administrator and incoming trafﬁc that is sent in response to requests from internal systems. Firewalls use complex ﬁltering algorithms that analyze incoming network data based on destination and source addresses, port numbers, and data type.
Software ﬁrewalls can be useful for small home offices and businesses. The ﬁrewall provides many features that can be conﬁgured to suit various computing needs. Some features include:
- Enabling or disabling port security on certain ports.
- Inbound and outbound ﬁltering. The user can set up rules or exceptions in the ﬁrewall settings to limit access to the web.
- Reporting and logging activity.
- Malware and spyware protection.
- Pop-up blocking.
- Port assigning, forwarding, and triggering.
A hardware ﬁrewall is a hardware device, either stand-alone or built into most routers, that protects computers on a private network from unauthorized traffic. They are placed between the private network and the public network to manage inbound and outbound traffic and network access.