IPPROTO_IP(2const) IPPROTO_IP(2const)

IPPROTO_IP - Linux IPv4 protocol socket options

Standard C library (libc-lc)

#include <netinet/in.h>  /* Definition of IP* constants */
#include <sys/socket.h>
int setsockopt(int sockfd, IPPROTO_IP, int opt,
               const void val[size], size_t size);
int getsockopt(int sockfd, IPPROTO_IP, int opt,
               void val[size], size_t size);

IP supports some protocol-specific socket options that can be set with setsockopt(2) and read with getsockopt(2). The socket option level for IP is IPPROTO_IP.

The following socket options are supported.

See setsockopt(2). See ip(7).

opt is invalid.

POSIX.1-2001.

setsockopt(2), ip(7)

2026-01-05 Linux man-pages 6.17