Show whether IPv4 forwarding is enabled
Build a paste-ready command, then review its compatibility and effects before running it.
sysctl net.ipv4.ip_forwardread-onlyno known side effects Compatibility
LinuxVerified for Linux using posix, bash, zsh syntax.
Operational knowledgereview due 2027-01-20
Requirementssysctlsysctl must be installed and available on PATH.
Version supportsysctl Current supported releasesVerified for linux using posix, bash, zsh syntax; consult compatibility notes for platform-specific differences.
Expected signalsnet.ipv4.ip_forward = 0Representative successful output; values vary with the selected target and system state.
Known errorssysctl: command not foundsysctl is missing or is not available on PATH.
Verifysysctl net.ipv4.ip_forwardThe output matches the expected target and exits without an error.Rollback noteNot required: this command is read-only and does not change system state.
Command breakdown
01sysctlCommandRuns the sysctl stage of this one-liner.
02net.ipv4.ip_forwardArgumentPasses net.ipv4.ip_forward to sysctl.
Example input
sysctl net.ipv4.ip_forward
Example output
net.ipv4.ip_forward = 0
Illustrative output — exact values vary by system and data.
Official sources