A firewall controls traffic by blocking or allowing ports. Usingufw(for Ubuntu/Debian) Allow specific ports: sudo ufw allow 22/tcp Deny specific ports: sudo ufw deny 23/tcp Enable firewall: sudo ufw enable For more detailed guide, please check the following link: How To Setup Firewall With...
If port 587 remains blocked, consider using other ports provided by your email service provider. Common alternatives include port 465 and port 25. Using Port 587 at Hostinger The email server configuration differs from one hosting service provider to another. Some companies allow port 587, while o...
Before we’ll be able to work with Checkmk, it’s necessary to allow outside access to the web server in the firewall configuration. Assuming that you followed the firewall configuration steps in the prerequisites, you’ll have a UFW firewall set up to restrict access to your serve...
sudotail-f/var/log/ufw.log The new fieldsSPTandDPT,which were not explained previously, show the source and destination ports. A different command to read UFW logs usinggrepwould be: grep-iufw/var/log/syslog Or the following command: grep-iufw/var/log/messages You also can run: grep-i...
sudoufw allow Apache Copy Now verify the changes: sudoufw status Copy You’ll see that Apache is listed among the allowed services: Output Status: active To Action From -- --- --- OpenSSH ALLOW Anywhere Apache ALLOW Anywhere OpenSSH