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Linux · Networking
How to check firewall rules in Linux
Check the active firewall rules with firewall-cmd on RHEL/Oracle Linux, ufw on Ubuntu, and nft as the low-level view.
See what the firewall allows. RHEL / Oracle Linux use firewalld; Ubuntu commonly uses ufw; both sit on top of nftables. Check whichever your system runs.
# firewalld (RHEL / Oracle Linux)
sudo firewall-cmd --state
sudo firewall-cmd --list-all
# ufw (Ubuntu / Debian)
sudo ufw status verbose
# Low-level nftables ruleset
sudo nft list ruleset
# Legacy iptables view
sudo iptables -L -n -vLinuxfirewalldFirewall