The IBM® Connect:Direct® Server binds a local socket for out-bound processes and typically this ANYADDR or unless the NETMAP parameter SOURCEIP is specified. A new global initialization parameter exists, TCP.SOURCEIP, to be a global default.

The intent of TCP.SOURCEIP is to define a global default IP address that the Connect:Direct for z/OS® server can bind to for out-bound IP processes so that each individual NETMAP entry does not require the SOURCEIP parameter unless there is a requirement to override the default. Assigning ANYADDR and/or ANYADDR6 for this parameter, is accepted and used, but defeats the purpose of the parameter.

There are three ways to obtain the local IP (TALOCAL_IP/RATLADDR) which is the local IP address for the Bind:
  • NETMAP SOURCEIP parameter
  • Hostname
Note: Services do not exist to obtain a hostname for IPv6.
The bind port currently is obtained in one of these two ways:
  • Bind to port zero(0) - default and most common
  • As defined by the TCP.SRC.PORTS initialization parameter
The binding to port zero causes TCP/IP itself to assign the port from a defined range or pool of ports ranging from 1024 to 65365. This port is reference as an ephemeral port and as far as a IBM Connect:Direct servers it appears to be randomly assigned. The TCP.SRC.PORTS is used to define a smaller pool of ports to be used.