IP_BIND_ADDRESS_NO_PORT(2const)                IP_BIND_ADDRESS_NO_PORT(2const)

NAME
       IP_BIND_ADDRESS_NO_PORT - don't reserve an ephemeral port

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_BIND_ADDRESS_NO_PORT,
                      const int *enable, sizeof(int));

DESCRIPTION
       Inform the kernel to not reserve an ephemeral port when using bind(2)
       with a port number of 0.  The port will later be automatically chosen
       at connect(2) time, in a way that allows sharing a source port as long
       as the 4-tuple is unique.

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

HISTORY
       Linux 4.2.

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

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