How to Check Telnet Service in a Sun Solaris Server

Solaris 10 uses its Service Management Facility (SMF) to start and stop services, including the telnet service. The telnet service allows users to log in to the Solaris system over the network using the telnet protocol, which is no longer widely used because the connection is not encrypted. By default, Solaris 10 disables the telnet service. Although most Solaris users run ssh (secure shell) instead of telnet, those who need to check and enable the telnet service can still do so. In just a few steps, you can check on the status of the telnet service.

Difficulty: Moderate

Instructions

1. Log into the Sun Solaris system as the root user. Root is the administrator account in a Solaris system.
   
   Although you can check the status of the telnet service as a nonroot user, you cannot change the status of the telnet service without being root.

2. Click on the Launch button, and then click on Applications. Click Utilities. Finally click Terminal, which brings up a command line window.
   
   The command line window allows you to run Solaris commands via text.

3. In the command line window, type "svcs -a | grep telnet."
   
   This SMF command displays the status of the telnet service. The status will be disabled, online, or in maintenance mode. Any Solaris user can run this command.
   
   If the telnet service is enabled, any user can log into the Solaris system using the telnet protocol. When the Solaris system reboots with telnet enabled, the telnet service starts up automatically.
   
   If the telnet service is disabled, users will no longer be allowed to use the telnet service. Any users already logged in using the telnet protocol remain online until they finally disconnect. When the Solaris system reboots with telnet disabled, the telnet service remains disabled until its status is changed by the root user.
   
   If the telnet service is in maintenance mode, the telnet service malfunctioned earlier and was stopped by the system.

Tips & Warnings

• If you need to enable the telnet service, log in as user root and type "svcadm enable telnet."
• If you need to disable the telnet service, log in as user root and type "svcadm disable telnet."
• Because telnet's network connection is unencrypted, using it as a service poses a serious security risk for the Sun Solaris system. A hacker can use a network sniffer on telnet connections to steal usernames and passwords, including the root account.

References

• Using Service Management Facility

Resources

• Solaris Service Management Facility - Quickstart Guide