IPPROTO_IPV6(2const)                                      IPPROTO_IPV6(2const)

NAME
       IPPROTO_IPV6 - Linux IPv6 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_IPV6, int opt,
                      const void val[size], size_t size);
       int getsockopt(int sockfd, IPPROTO_IPV6, int opt,
                      void val[size], size_t size);

DESCRIPTION
       IPv6 supports some protocol-specific socket options that can be set
       with setsockopt(2) and read with getsockopt(2).  The socket option
       level for IPv6 is IPPROTO_IPV6.  A boolean integer flag is zero when it
       is false, otherwise true.

       The following socket options are supported.

       IPV6_ADDRFORM(2const)
       IPV6_ADD_MEMBERSHIP(2const)
       IPV6_DROP_MEMBERSHIP(2const)
       IPV6_MTU(2const)
       IPV6_MTU_DISCOVER(2const)
       IPV6_MULTICAST_HOPS(2const)
       IPV6_MULTICAST_IF(2const)
       IPV6_MULTICAST_LOOP(2const)
       IPV6_RECVPKTINFO(2const)
       IPV6_RTHDR(2const)
       IPV6_AUTHHDR(2const)
       IPV6_DSTOPTS(2const)
       IPV6_HOPOPTS(2const)
       IPV6_FLOWINFO(2const)
       IPV6_HOPLIMIT(2const)
       IPV6_RECVERR(2const)
       IPV6_ROUTER_ALERT(2const)
       IPV6_UNICAST_HOPS(2const)
       IPV6_V6ONLY(2const)

ERRORS
       See setsockopt(2).  See ipv6(7).

       ENOPROTOOPT
              opt is invalid.

HISTORY
       IPPROTO_IPV6
              POSIX.1-2001.

SEE ALSO
       setsockopt(2), cmsg(3), ipv6(7)

Linux man-pages 6.17              2026-01-05              IPPROTO_IPV6(2const)