AI Knowledge Hubfirewall-cmd — Manage firewalld rules
Inspects and applies firewalld zones, services and port rules from the command line.
Inspects and applies firewalld zones, services and port rules from the command line.
Basic Information
| Command Name | firewall-cmd |
|---|---|
| One-line Introduction | Inspects and applies firewalld zones, services and port rules from the command line. |
| Provided by | firewalld project (default on RHEL family) |
| Official Documentation | https://firewalld.org/documentation/man-pages/firewall-cmd.html |
| Supported Operating Systems | Linux (firewalld) |
| Installation Status | Requires firewalld (apt install firewalld) |
| Category | Linux networking (tags: Address, port and firewall management (tags: firewall, zone, port, rule)) |
What is this command?
firewall-cmd is the client that queries and changes rules in the firewalld daemon.
Rules exist at runtime and in permanent configuration; permanent ones apply after a reload.
What problems does it solve?
- Open a port or service for allowed traffic.
- List every rule in the active zone.
- Persist runtime rules into the permanent configuration.
- Allow only one source network.
Key features
Runtime rules
Without --permanent a change applies at once and disappears on restart.
- When to use: For a temporary opening.
- What you get: Traffic passes immediately.
- Limitations: It is lost after restart or reload.
Permanent rules
Save with --permanent, then apply with --reload.
- When to use: When the rule must survive reboots.
- What you get: The rule is written to configuration and persists.
- Limitations: It does not affect traffic until reloaded.
Zone management
Assign interfaces and sources to zones to separate policies.
- When to use: When internal and external networks differ.
- What you get: Each zone enforces its own rules.
- Limitations: Wrong zone priority applies unintended rules.
Installation and usage
Check whether it is installed
firewall-cmd --version
sudo apt install firewalld
Real-world examples
Check state
Show daemon state and default zone.
firewall-cmd --state && firewall-cmd --get-default-zone
Open a port
Open 8080/tcp permanently.
firewall-cmd --permanent --add-port=8080/tcp && firewall-cmd --reload
List rules
List allowed services and ports in the zone.
firewall-cmd --list-all
Source (HTML): https://games.aidebatehub.com/programs/linux/network/firewall-cmd.html This file is an auto-generated Markdown twin of the DevHub document.
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