Kernel Configuration

You configure the OpenBSD kernel via text files. Like 4.4BSD, OpenBSD doesn’t offer a fancy graphical kernel configuration utility or menu-driven system. Each kernel configuration is on a single line, along with a label indicating the type of entry and a description. Pound signs (#) mark comments.

Configuration Entries

Kernel configuration entries fall into four general categories: options, device drivers, pseudo-devices, and keywords.


Options are hardware-independent kernel functions. Options handle things like filesystems, networking protocols, and compatibility layers.

Option entries look like this:

option     FFS         # UFS
option     INET        # IP + ICMP + TCP + UDP
option     CRYPTO      # Cryptographic framework

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