IP_TRANSPARENT

Standard C library (libc, -lc)

#include <netinet/in.h>  /* Definition of IP* constants */
#include <sys/socket.h>

int setsockopt(int sockfd, IPPROTO_IP, IP_TRANSPARENT,
               const int *enable, sizeof(int));

Setting this boolean option enables transparent proxying on this socket.

This socket option allows the calling application to bind to a nonlocal IP address and operate both as a client and a server with the foreign address as the local endpoint.

This requires that routing be set up in a way that packets going to the foreign address are routed through the TProxy box (i.e., the system hosting the application that employs the IP_TRANSPARENT socket option).

Enabling this socket option requires superuser privileges (the CAP_NET_ADMIN or CAP_NET_RAW capability).

TProxy redirection with the iptables TPROXY target also requires that this option be set on the redirected socket.

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

Linux.

Linux 2.6.24.

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