Firewall ​

Additional firewall notes are summarized in network notes.

For linux, iptables is a tried-and-true solution for a system firewall. Included by default in debian / ubuntu.

https://www.digitalocean.com/community/tutorials/iptables-essentials-common-firewall-rules-and-commands

See currently configured rules

iptables -nvL | less

iptables -nvL | less

Netfilter is the official name for the project that maintains iptables and its successor, nftables

https://www.netfilter.org/

https://github.com/trimstray/iptables-essentials
trimstray/iptables-essentials: Iptables Essentials: Common Firewall Rules and Commands.
https://major.io/2010/04/12/best-practices-iptables/
Best practices: iptables | Major Hayden
https://duckduckgo.com/?t=ffab&q=iptables+init+&ia=web
iptables init at DuckDuckGo
https://github.com/BorX/iptables-init
BorX/iptables-init: Easy initialization iptables rules
https://github.com/topics/iptables
iptables · GitHub Topics

https://github.com/topics/firewall
firewall · GitHub Topics

https://docs.opnsense.org/development/architecture.html Architecture — OPNsense documentation https://github.com/opnsense/core GitHub - opnsense/core: OPNsense GUI, API and systems backend

https://ubuntu.com/server/docs/security-firewall Security - Firewall | Ubuntu