IPSecurity (IPSec)

IPSec is a network layer protocol suite that secures Internet connections by encrypting IP packets. IPSec is an optional part of IPv4 (page 1038) and a required part of IPv6 (page 1038). See page 995 for more information on IPSec.

Kernel integration of IPSec means that any kernel module or application can use IPSec in the same way that it would use unsecured IP.

Native Posix Thread Library (NPTL)

Asynchronous I/O (AIO)