Defining a TCP connection on IBM i

You can define a TCP connection within the channel definition using the Connection Name field.

The channel definition contains a field, CONNECTION NAME, that contains either the TCP network address of the target or the host name (for example ABCHOST). The TCP network address can be in IPv4 dotted decimal form (for example 127.0.0.1) or IPv6 hexadecimal form (for example 2001:DB8:0:0:0:0:0:0). If the CONNECTION NAME is a host name or a name server, the IBM® i host table is used to convert the host name into a TCP host address.

A port number is required for a complete TCP address; if this number is not supplied, the default port number 1414 is used. On the initiating end of a connection (sender, requester, and server channel types) it is possible to provide an optional port number for the connection, for example:


Connection name 127.0.0.1 (1555)

In this case the initiating end attempts to connect to a receiving program at port 1555.

Using the TCP listener backlog option

In TCP, connections are treated incomplete unless three-way handshake takes place between the server and the client. These connections are called outstanding connection requests. A maximum value is set for these outstanding connection requests and can be considered a backlog of requests waiting on the TCP port for the listener to accept the request.

See Using the TCP listener backlog option for more information, and the specific value for IBM i.