System Administration Guide

Port Monitors

The main mechanism for gaining access to a service is through a port monitor. A port monitor is a program that continuously monitors for requests to log in or access printers or files.

When a port monitor detects a request, it sets whatever parameters are required to establish communication between the operating system and the device requesting service. Then the port monitor transfers control to other processes that provide the services needed.

Table 47-1 describes the two types of port monitors included in the Solaris 2.x environment.

Table 47-1 Port Monitor Types


Port Monitor	Description
listen(1M)	Controls access to network services, handling remote print and file system requests. A common use of the `listen` port monitor is to listen for requests from the LP print service. For more information on the `listen` port monitor, see Chapter 49, Setting Up Terminals and Modems With the Service Access Facility (Tasks).The `listen` port monitor is not used when you set up modems and alphanumeric terminals.
ttymon(1M)	Provides access to the login services needed by modems and alphanumeric terminals. Solstice Serial Port Manager automatically sets up a `ttymon` port monitor to process login requests from these devices. Using Solstice Serial Port Manager to set up terminals and modems is described in Chapter 48, Setting Up Terminals and Modems (Tasks).

You may be familiar with an older port monitor called getty(1M). The new ttymon is more powerful; a single ttymon can replace multiple occurrences of getty. Otherwise, these two programs serve the same function.