IP_LOCAL_PORT_RANGE(2const) — Linux manual page

IP_LOCAL_PORT_RANGE(2const)                   IP_LOCAL_PORT_RANGE(2const)

NAME         top

       IP_LOCAL_PORT_RANGE - default local port range

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_LOCAL_PORT_RANGE,
                      const uint32_t *val, sizeof(uint32_t));
       int getsockopt(int sockfd, IPPROTO_IP, IP_LOCAL_PORT_RANGE,
                      uint32_t *val, sizeof(uint32_t));

DESCRIPTION         top

       Set or get the per-socket default local port range.

       This option can be used to clamp down the global local port range,
       defined by the /proc/sys/net/ipv4/ip_local_port_range interface,
       for a given socket.

       The option takes an uint32_t value with the high 16 bits set to
       the upper range bound, and the low 16 bits set to the lower range
       bound.  Range bounds are inclusive.  The 16-bit values should be
       in host byte order.

       The lower bound has to be less than the upper bound when both
       bounds are not zero.  Otherwise, setting the option fails with
       EINVAL.

       If either bound is outside of the global local port range, or is
       zero, then that bound has no effect.

       To reset the setting, pass zero as both the upper and the lower
       bound.

ERRORS         top

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

HISTORY         top

       Linux 6.3.

SEE ALSO         top

       IPPROTO_IP(2const), setsockopt(2), proc_sys_net_ipv4(5), ip(7)

COLOPHON         top

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

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

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