---
name: "sysctl.conf"
section: "5"
platform: "openbsd"
package: "man"
version: "8.0-current-20261101"
release: "OpenBSD 8.0-current (2026-11-01)"
platforms: ["linux", "freebsd", "openbsd", "macos"]
url: "https://new.carta.tech/sysctl.conf"
---

# sysctl.conf(5)

sysctl variables to set at system startup

## NAME

**sysctl.conf** – sysctl variables to set at system startup

## DESCRIPTION

**sysctl.conf** is made up of [sysctl(8)](/sysctl/8.md) variable assignments (*variable*=*value*) with comments designated by a hash mark (‘#’).

*/etc/sysctl.conf* is read at system startup by [rc(8)](/rc/8.md) early on in the boot sequence.

## FILES

- */etc/sysctl.conf*

  - */etc/examples/sysctl.conf*

  ## EXAMPLES

To turn on IP forwarding, one would use the following line:

```
net.inet.ip.forwarding=1
```

To cause the kernel to reboot on a panic, instead of dropping into the debugger, the following can be used:

```
ddb.panic=0
```

## SEE ALSO

[sysctl(2)](/sysctl/2.md), [rc(8)](/rc/8.md), [sysctl(8)](/sysctl/8.md)

## HISTORY

A **sysctl.conf** file first appeared in OpenBSD 2.3.