Session Establishment

Session establishment affects how you set up firewall rules and configure the firewall navigation initialization parameters in IBM® Connect:Direct®.

TCP Session Establishment

A IBM Connect:Direct TCP client contacts a IBM Connect:Direct TCP server on its listening port. The IBM Connect:Direct client scans the list of ports (specified using the TCP.SRC.PORTS initialization parameter) and looks for a port to bind to. The number of times IBM Connect:Direct scans the list is specified using the TCP.SRC.PORTS.LIST.ITERATIONS initialization parameter. If IBM Connect:Direct finds an available port, communication with the remote node proceeds.

Common Problems in Establishing a Session

The following message indicates that IBM Connect:Direct cannot find an idle port.

SCPA001I - TGT.ADDR=nnn.nnn.nnn.nnn, TCP.SRC.PORTS exhausted

If this message occurs frequently, increase the pool of available ports.

You may need to reserve ports in TCP/IP to ensure they are available for firewall navigation. Reserve ports with the PORT statement in IBM TCP/IP. An example follows:

PORT
   5000 TCP connect-jobname   NOAUTOLOG  ; Connect:Direct Firewall pool
   5001 TCP connect-jobname   NOAUTOLOG  ; Connect:Direct Firewall pool
   5002 TCP connect-jobname   NOAUTOLOG  ; Connect:Direct Firewall pool
   5003 TCP connect-jobname   NOAUTOLOG  ; Connect:Direct Firewall pool
   5004 TCP connect-jobname   NOAUTOLOG  ; Connect:Direct Firewall pool
   5005 TCP connect-jobname   NOAUTOLOG  ; Connect:Direct Firewall pool

A pool of available ports that is too small can affect performance because the outbound connections are limited.