Add a reusable iptables baseline that hardens hosts with ICMP + SSH
defaults and lets deployments register the ports they need. INPUT is
deny-by-default (loopback, established, ICMP, SSH on the configured port,
plus registered ports); OUTPUT stays open and FORWARD is left untouched so
Docker container networking is unaffected.
Persistence is native -- no boot hook. Rules are saved and restored by the
distro's own package (iptables/ip6tables on Alpine, iptables-persistent on
Debian, iptables-services on Alma) via the new oslib helpers
install_iptables / fw_save_cmd / fw_enable_restore. The saved ruleset
carries the INPUT->sshguard jump, so brute-force protection survives reboot
without the old sshguard-iptables hook.
A self-contained /usr/local/sbin/firewall-apply rebuilds INPUT from
declarative drop-ins under /etc/firewall/ports.d and runs the native save,
so deployments add a port without needing the repo present:
printf '80/tcp\n443/tcp\n' > /etc/firewall/ports.d/mystack.rule
/usr/local/sbin/firewall-apply
- SSH port read live from sshd_config (custom bastion ports just work);
FW_SSH_SOURCE restricts the source CIDR; FW_ALLOW_PING gates echo
- harden-ssh.sh / harden-jumphost.sh install it when ENABLE_FIREWALL=1
(default) and skip the sshguard-only hook; ENABLE_FIREWALL=0 keeps it
- cloud-init base.yml / jumphost.yml forward the toggle
- the four stack deploy.sh open_web_ports() register 80/443 via the
firewall (ufw/firewalld kept as fallback); Docker-published ports bypass
INPUT, so this is belt-and-braces and self-documenting
- README + cloud-init/README document the mechanism, Docker caveat, and the
`disable` recovery path
57_Wolve
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