NAME

       zmq_tcp - 0MQ unicast transport using TCP

SYNOPSIS

       TCP is an ubiquitous, reliable, unicast transport. When connecting distributed applications over a
       network with 0MQ, using the TCP transport will likely be your first choice.

ADDRESSING

       A 0MQ endpoint is a string consisting of a transport:// followed by an address. The transport specifies
       the underlying protocol to use. The address specifies the transport-specific address to connect to.

       For the TCP transport, the transport is tcp, and the meaning of the address part is defined below.

   Assigning a local address to a socket
       When assigning a local address to a socket using zmq_bind() with the tcp transport, the endpoint shall be
       interpreted as an interface followed by a colon and the TCP port number to use.

       An interface may be specified by either of the following:

       •   The wild-card *, meaning all available interfaces.

       •   The primary IPv4 or IPv6 address assigned to the interface, in its numeric representation.

       •   The non-portable interface name as defined by the operating system.

       The TCP port number may be specified by:

       •   A numeric value, usually above 1024 on POSIX systems.

       •   The wild-card *, meaning a system-assigned ephemeral port.

       When using ephemeral ports, the caller should retrieve the actual assigned port using the
       ZMQ_LAST_ENDPOINT socket option. See zmq_getsockopt(3) for details.

   Unbinding wild-card address from a socket
       When wild-card * endpoint was used in zmq_bind(), the caller should use real endpoint obtained from the
       ZMQ_LAST_ENDPOINT socket option to unbind this endpoint from a socket using zmq_unbind().

   Connecting a socket
       When connecting a socket to a peer address using zmq_connect() with the tcp transport, the endpoint shall
       be interpreted as a peer address followed by a colon and the TCP port number to use. You can optionally
       specify a source_endpoint which will be used as the source address for your connection;
       tcp://source_endpoint;'endpoint', see the interface description above for details.

       A peer address may be specified by either of the following:

       •   The DNS name of the peer.

       •   The IPv4 or IPv6 address of the peer, in its numeric representation.

       Note: A description of the ZeroMQ Message Transport Protocol (ZMTP) which is used by the TCP transport
       can be found at http://rfc.zeromq.org/spec:15

EXAMPLES

       Assigning a local address to a socket.

           //  TCP port 5555 on all available interfaces
           rc = zmq_bind(socket, "tcp://*:5555");
           assert (rc == 0);
           //  TCP port 5555 on the local loop-back interface on all platforms
           rc = zmq_bind(socket, "tcp://127.0.0.1:5555");
           assert (rc == 0);
           //  TCP port 5555 on the first Ethernet network interface on Linux
           rc = zmq_bind(socket, "tcp://eth0:5555");
           assert (rc == 0);

       Connecting a socket.

           //  Connecting using an IP address
           rc = zmq_connect(socket, "tcp://192.168.1.1:5555");
           assert (rc == 0);
           //  Connecting using a DNS name
           rc = zmq_connect(socket, "tcp://server1:5555");
           assert (rc == 0);
           //  Connecting using a DNS name and bind to eth1
           rc = zmq_connect(socket, "tcp://eth1:0;server1:5555");
           assert (rc == 0);
           //  Connecting using a IP address and bind to an IP address
           rc = zmq_connect(socket, "tcp://192.168.1.17:5555;192.168.1.1:5555");
           assert (rc == 0);

SEE ALSO

       zmq_bind(3) zmq_connect(3) zmq_pgm(7) zmq_ipc(7) zmq_inproc(7) zmq_vmci(7) zmq(7)

AUTHORS

       This page was written by the 0MQ community. To make a change please read the 0MQ Contribution Policy at
       http://www.zeromq.org/docs:contributing.

0MQ 4.2.5                                          07/03/2019                                         ZMQ_TCP(7)