Linux Server / Networking, SSH & Web Services
Inspect nftables rules before assuming the Linux firewall is open
A service can listen correctly while an effective ruleset drops its traffic. Read the actual rules and counters in the right namespace.
Environment and inputs: Linux server baseline · Ubuntu 24.04 LTS / RHEL 9-style systems. Use the specified distribution, init system and installed tool; service names, privileges and supported options can differ.
Start with this check
Confirm the host, shell and access role. Replace sample names, paths, domains and interfaces with approved targets. These are diagnostic commands; assess policy and workload impact before making changes.
nft list rulesetRead the result
With authorized privileges on a system using nftables, this prints the ruleset. A higher-level manager may own the rules and regenerate them.
Resolve and verify
Match the affected direction, interface, protocol and port with counters and permitted test traffic. Make a narrow correction through the managing firewall system.
Before changing production
Do not flush the ruleset or add broad accepts during remote troubleshooting; it can expose services or break managed networking.