IP_HDRINCL(2const) — Linux manual page

IPPROTO_IP(2const)                                     IPPROTO_IP(2const)

NAME         top

       IPPROTO_IP - include a user-supplied IP header

LIBRARY         top

       Standard C library (libc, -lc)

SYNOPSIS         top

       #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         top

       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         top

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

HISTORY         top

       Linux 2.0.

SEE ALSO         top

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

COLOPHON         top

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Linux man-pages 6.18            2025-11-25             IPPROTO_IP(2const)

Pages that refer to this page: IP_PASSSEC(2const),  IPPROTO_IP(2const)

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