Nagios Plugins

Nagios is a popular open source computer system and network monitoring software application. It watches hosts and services, alerting users when things go wrong and again when they get better.

The Nagios architecture supports the use of community-developed plugins to monitor services and systems not supported by the core tools. After identifying a need for a simple SFTP connection monitor, we developed check_sftp_avail. This Nagios plugin is now made available to anyone that wishes to use it.

Please note that neither Nagios or this plugin are intended for end users. Nagios is more of a systems adminstrator tool and you will only find this plugin helpful if you are currently using Nagios.

Check SFTP availability: check_sftp_avail

This plugin will attempt to get a login prompt via sftp. Unlike the more complete check_sftp plugin it does not require a user name and password and therefore does not verify login capability. This plugin is intended to be used in an environment where protecting login credentials and/or keeping up with frequently changing passwords can become an administrative headache. As a result check_sftp_avail merely checks whether the sftp service is running and that a login prompt is obtainable remotely.

Another difference between check_sftp_avail and check_sftp is that check_sftp_avail is completely standalone and does not require the installation of any other dependencies.

check_sftp_avail is written as a simple shell script. You can view the source script for check_sftp_avail by clicking on the previous link, or save it to your hard disk by right-clicking the link and selecting Save Link As.


  • Right click on the link for check_sftp_avail and select Save Link As. Then save it somewhere on your hard disk.
  • Move the file downloaded into your nagios plugins directory. For example, under /usr/lib/nagios/plugins. [Note that you will need to be logged in as a user that has write access to this directory.]
  • Change the ownership and group if needed for your particular Nagios installation.
  • Make sure that the file is marked as executable: chmod 755 check_sftp_avail

At this point the installation is complete. You can test it from the nagios plugins directory by typing:

./check_sftp_avail -H sftp_host_to_check

To use the plugin from Nagios, you can define a commandfor check_sftp_avail by adding the following to your commands.cfg or similar file:

# 'check_sftp_avail' command definition 
define command{
command_name check_sftp_avail
command_line $USER1$/check_sftp_avail -H $HOSTADDRESS$

 Finally configure the host(s) that you want nagios to check for sftp service availability.