How to limit range of random port sockets

Apache supports several special debugging defines, to be used with -D:

• NO_DETACH: Don’t detach from the controlling terminal.
• FOREGROUND: (implies NO_DETACH): Don’t daemonize or detach from the controlling terminal
• ONE_PROCESS (implies NO_DETACH and FOREGROUND): Don’t allow a child process to handle client requests; use the initial process instead.
• DEBUG (implies all of the previous): Places the MPM into a special debug mode with additional logging.

Thus, running "httpd -D FOREGROUND" will keep it from daemonizing.

I also ran into a forum thread with a launchd plist for Apache2 that you might be able to adapt.

(Note: I know neither of these answer the actual question, but hopefully they're useful for the problem initially described.)

Technically, there's no such thing as a "reserved port".

In TCP/UDP, the only way to "reserve" a port is to actually bind() a socket to it. A bound port will not be used by other applications; an unused port is, well, unused so other applications are free to use it.

If you are writing server software, then you can bind your sockets to specific ports as early as you want in the application code. Make the port numbers configurable, or at least clearly state them in the documentation, so that a systems administrator can quickly identify clashes and move conflicting applications to separate servers.