Network Kernel Extensions

The kernel supports extending the network stack at multiple levels through the Network Kernel Extensions (NKE) mechanism. An NKE is no different from a regular KEXT; it is merely a term used to describe a KEXT that interfaces with or extends the network stack.

As such, NKEs are also dynamically loadable and unloadable at runtime. NKEs are not part of the I/O Kit, but located in the BSD layer. The NKE mechanism is unique to Mac OS X and not found in BSD UNIX flavors, such as FreeBSD.

An NKE can be used for many purposes. Some examples of use include, but are not limited to, the following:

  • Custom firewall or security mechanisms, such as encryption
  • Adding support for new protocols
  • Adding support for new network interfaces ...

Get OS X and iOS Kernel Programming now with the O’Reilly learning platform.

O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.

Start your free trial