telmon

What is it?

Telmon is a simple golang daemon that will monitor a given telnet connection from a telnet client to a telnet server. It reports any loss in connection via email to a list of receivers.

How to use it.

1. Installation.

Install telmon binary from GitHub. In this tutorial, we will be using the linux OS builds.

wget https://github.com/jackkweyunga/telmon/releases/download/v0.1/telmon_0.1_Linux_x86_64.tar.gz

Extract to /usr/local/bin/

sudo tar -C /usr/local/bin -xzf telmon_0.1_Linux_x86_64.tar.gz telmon

test it. If you see a message as one below, shows that it's working.

$ telmon
2022/10/07 09:49:57 Config File ".telmon-config" Not Found in ...

• visit the releases page for system specific downloads.

In order to use telmon, create a configuration file .telmon-config.yaml in any directory in which you will run the telmon binary.

2. Configurations

create a .telmon-config.yaml configuration file in any directory accessible by the user. Home directory is better.

$ nano .telmon-config.yaml

The content of the configuration file should be as follows.

---
addr: example.com
port: <telnet-port>
email: <sender-email>
password: <sender-email-password>
receivers:
  - user-1@example.com
  - user-2@example.com

3. Run

$ telmon

sample output

$ telmon
Monitoring Service started successfully ...
[2022-10-07T09:56:09+03:00] running
[TelnetClient] Trying to connect to telnet server.
[TelnetClient] Encountered errors while connecting:
dial tcp 192.241.152.67:23: connect: connection refused
Reporting this error
[TelnetClient] Report sent successfully

4. Supervisord

Supervisord helps to monitor and control running processes in any linux machine. For linux users, add a supervisord configuration file to monitor telmon.

create a file /etc/supervisord/conf.d/telmon.conf

Add the content below.

[program:telmon]
directory=/path/to/your/telmon/directory
command=telmon
autostart=true
autorestart=true
stderr_logfile=/var/log/telmon.err.log
stdout_logfile=/var/log/telmon.out.log

Reload supervisord configurations.

supervisorctl reread
supervisorctl update

OR .. reload supervisor

supervisorctl reload

Credits

• The viper project
• The go-telnet project