This is the first day of my participation in the August Challenge. For details, see:August is more challenging

Today I would like to share with you the common failures encountered when using the Linux system, as well as the handling methods for the failures. I hope it helps. These failures are derived from practice, but also hope that we communicate more, more questions, we make progress together!

1. How to determine whether a port is played through?

In addition to checking the local firewall and cloud Console security group, you can connect through Telnet

2. How to query which files are large when the disk is full?

Du -h - max-depth=1 * # Query the total size of the current directory. Du -sh # Displays the size of files and folders in the current subdirectory. Du -h - max-depth=0 *Copy the code

3. How do I Query server logs?

Run the tailf /var/log/messages command

4. What should I do if service startup fails?

When the Linux service fails to be started, the system prompts you to run the journalctl -xe command to query the detailed information and locate the cause.

5. Repeatedly refreshing the page using the same IP address causes server 403 error handling

Mod_evasive Apache module of defense against attack, which helps prevent DoS, DDoS, and violent attacks against the Apache server. It can provide evasive action during attacks and report abuse through email and system logging tools. This module works by creating an internal dynamic table of IP addresses and URIs and rejecting any of the following IP addresses:

  • The same page is requested multiple times per second
  • More than 50 concurrent requests per second to the same child
  • Any request for temporary blacklisting

If any of the above conditions are met, a 403 response is sent and the IP address is recorded.

View the List of Apache modules
apachectl -M
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Modifying configuration Items

Find the mod_evasive. Conf file in the conf.d directory and configure it (only if you want to bear with the website)

This article is originally published by Websoft9.