IPPROTO_IP(2const)                                          IPPROTO_IP(2const)

NAME
       IPPROTO_IP - Linux IPv4 protocol socket options

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, int opt,
                      const void val[size], size_t size);
       int getsockopt(int sockfd, IPPROTO_IP, int opt,
                      void val[size], size_t size);

DESCRIPTION
       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.

       IP_ADD_MEMBERSHIP(2const)
       IP_ADD_SOURCE_MEMBERSHIP(2const)
       IP_BIND_ADDRESS_NO_PORT(2const)
       IP_BLOCK_SOURCE(2const)
       IP_DROP_MEMBERSHIP(2const)
       IP_DROP_SOURCE_MEMBERSHIP(2const)
       IP_FREEBIND(2const)
       IP_HDRINCL(2const)
       IP_LOCAL_PORT_RANGE(2const)
       IP_MSFILTER(2const)
       IP_MTU(2const)
       IP_MTU_DISCOVER(2const)
       IP_MULTICAST_ALL(2const)
       IP_MULTICAST_IF(2const)
       IP_MULTICAST_LOOP(2const)
       IP_MULTICAST_TTL(2const)
       IP_NODEFRAG(2const)
       IP_OPTIONS(2const)
       IP_PASSSEC(2const)
       IP_PKTINFO(2const)
       IP_RECVERR(2const)
       IP_RECVOPTS(2const)
       IP_RECVORIGDSTADDR(2const)
       IP_RECVTOS(2const)
       IP_RECVTTL(2const)
       IP_RETOPTS(2const)
       IP_ROUTER_ALERT(2const)
       IP_TOS(2const)
       IP_TRANSPARENT(2const)
       IP_TTL(2const)
       IP_UNBLOCK_SOURCE(2const)

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

       ENOPROTOOPT
              opt is invalid.

HISTORY
       IPPROTO_IP
              POSIX.1-2001.

SEE ALSO
       setsockopt(2), ip(7)

Linux man-pages 6.17              2026-01-05                IPPROTO_IP(2const)