How to monitor logs and notify about critical events in linux?

Question

linux

Did you need to host 3 sites and the question arose of monitoring logs with notification by mail about accidents or hacking attempts?
How can this be done?

Answer 1

monitor

Answer 2

zabbix

Answer 3

gray log

Answer 4

1. To control unsuccessful login attempts, there is fail2ban , which bans the IP addresses of stubborn uninvited guests and knows how to send letters about it if necessary.
2. To analyze logs and send reports, there is logwatch , by default, it looks at logs once a day and sends a report letter to the local root, you can redirect it wherever you want.
3. To control the health of services, the state of the system, control arbitrary points of failure , zabbix was invented , but for one host this will be a difficult decision.
Perhaps the first two points will suffice to get you started.

Answer 5

in the simplest case - a script that will periodically run on the site, read the logs and send a letter to someone who needs it.

Answer 6

The logs always contain all attempts to enter the server, what is generally understood as a hacking attempt?