What can happen when port reservations are not processed.

This kind of problem can occur for multiple reasons (see TechNote 1594896 for the most likely cause). The resultant problems that can occur when this happens can include:

• The port intended to be reserved gets handed out as an ephemeral port. This can happen before a server application starts (more likely with lower port numbers), which will cause its bind to that port to fail (and typically the server to shut down).

• If the port statement specifies RESERVED instead of a job name to prevent a port's use, an application that is assigned it as an ephemeral port could then have some unpredictable failure. A typical problem can be the inability to go through a firewall to access an external server.

• A server using a port with a BIND keyword assigning a specific address will not get that address. If the application is intended to create a dynamic VIPA (the address is within a VIPARANGE), that does not occur. And depending on how any applicable VIPADISTRIBUTE statements are coded, it may not get associated with that processing.

• If the SAF keyword is used on port reservations, those protections will not take effect.

• If SHAREPORT is specified, only one server will start successfully (the secondary ones will fail).

You can use an OBEYFILE command to enable the intended set of port reservations by referencing a data set with the complete set of PORT statements. However any applications still running with a (typically listener) socket created while the port statements were missing will continue to have the above issues with that socket's port.