Safer Internet: Connection: Use a Firewall

Summary | Built-in Software | Block Ports | Other Software |
References: General | macOS | Windows

Summary

Routers typically provide some hardware firewall protection, plus a layer of anonymity.
[1] Enable your device's built-in software firewall; default (mostly inbound) settings are usually adequate
[2] Block/unblock specific ports/services via router or OS, e.g., if you're a gamer or server admin
[3] Install 3rd party software for more advanced inbound and/or outbound firewall
References

[1] Enable your device's built-in software firewall

iOS: not necessary
macOS: System Preferences > Security & Privacy > Firewall > Turn On
[screenshot] you'll need to click the lock and provide your admin password
macOS: {Figure 9. TCYOP-4: 76; TCYOP-3: 62}; Win: {Figure 8. TCYOP-4: 75; TCYOP-3: 61}

[2] Block/unblock specific ports/services

macOS: System Preferences > Security & Privacy > Firewall > Firewall Options [screenshot]

[3] Install 3rd party software

Install 3rd party software for more advanced inbound and/or outbound firewall {TCYOP-4: 66}
macOS: Little Snitch; Lulu; others: Intego NetBarrier; Murus; Norton Security; Radio Silence
macOS: access secondary built-in firewall pf via Terminal, or GUI: Murus
Windows: ZoneAlarm; Windows 8 Firewall Control

References

{TCYOP-4: 74-77; TCYOP-3: 61-63; Use an Outbound Firewall; Beware Analog Snooping, Too}
sections: Refs: macOS, Windows
Wikipedia: Firewall controls incoming and outgoing network traffic; router
Wikipedia: Firewalls and Internet security; Personal firewall
HowStuffWorks: How Firewalls Work

macOS

Apple: firewall
Little Snitch 6.1.2 TB; 10/17/2024
You Should Use a Firewall on Your Mac (but Not Apple's) LH; 10/15/2024
How to Enable or Disable Firewall on MacOS Ventura OSXD; 5/17/2023
Apple has removed a controversial feature in macOS 11.2 beta 2 that allowed its own apps to bypass third-party firewalls, security tools, and VPNs ZD; 1/14/2021

Win

Wikipedia: Windows firewall

Printer-friendly version