It is sometimes necessary to indicate which ports to use when opening a server connection through a firewall. You can use the CLIENTPORT clause of the CREATE PROCEDURE and CREATE FUNCTION statements to designate port numbers on which the client application communicates using TCP/IP. It is recommended that you not use this feature unless your firewall restricts access to a particular range of ports. For more information, see Web client SQL statements.

For example, run the following statement in the web client database to create an procedure named MyOperation that sends requests to the specified URL using one of the ports in the range 5050-5060, or port 5070:

CREATE PROCEDURE MyOperation ()
    URL 'HTTP://localhost:8020/dbname/SampleWebService'
    CLIENTPORT '5050-5060,5070';

It is recommended that you specify a range of port numbers when required. Only one connection is maintained at a time when you specify a single port number; the client application attempts to access all specified port numbers until it finds one to bind to. After closing the connection, a timeout period of several minutes is initiated so that no new connection can be made to the same server and port.

This feature is similar to setting the ClientPort network protocol option. See ClientPort (CPORT) protocol option.