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This section describes the details of the protocols and socket naming
conventions used in the Internet namespace.
Originally the Internet namespace used only IP version 4 (IPv4). With
the growing number of hosts on the Internet, a new protocol with a
larger address space was necessary: IP version 6 (IPv6). IPv6
introduces 128-bit addresses (IPv4 has 32-bit addresses) and other
features, and will eventually replace IPv4.
To create a socket in the IPv4 Internet namespace, use the symbolic name
PF_INET
of this namespace as the namespace argument to
socket
or socketpair
. For IPv6 addresses you need the
macro PF_INET6
. These macros are defined in sys/socket.h
.
int PF_INET | Macro |
This designates the IPv4 Internet namespace and associated family of protocols. |
int PF_INET6 | Macro |
This designates the IPv6 Internet namespace and associated family of protocols. |