IPPROTO_IP(2const)                                          IPPROTO_IP(2const)

NAME
       IPPROTO_IP - include a user-supplied IP header

LIBRARY
       Standard C library (libc, -lc)

SYNOPSIS
       #include <netinet/in.h>  /* Definition of IP* constants */
       #include <sys/socket.h>

       int setsockopt(int sockfd, IPPROTO_IP, IP_HDRINCL,
                      const int *enable, sizeof(int));

DESCRIPTION
       If enabled, the user supplies an IP header in front of the user data.

       Valid only for SOCK_RAW sockets; see raw(7) for more information.

       When this flag is enabled, the values set by IP_OPTIONS(2const),
       IP_TTL(2const), and IP_TOS(2const) are ignored.

ERRORS
       See IPPROTO_IP(2const).  See setsockopt(2).  See ip(7).

HISTORY
       Linux 2.0.

SEE ALSO
       IPPROTO_IP(2const), setsockopt(2), ip(7)

Linux man-pages 6.17              2025-11-25                IPPROTO_IP(2const)