How to change the Hostname on AlmaLinux 8, CentOS 8 and Rocky Linux 8

Change Hostname

The easiest way to change the hostname on AlmaLinux 8, CentOS 8, and Rocky Linux 8 is to use the hostnamectl command. First I will check the current hostname by running "hostnamectl status" on the shell of my server: hostnamectl status The output on my system is: [root@server1 ~]# hostnamectl status Static hostname: server1.example.com Icon ... Read more

How to convert RPM software packages to Debian (.deb) using alien

Maybe you have had this problem: you are using Debian or Ubuntu Linux and a software package you would like to install is only available in RPM format. The solution is the handy tool called alien, which converts .rpm files to .deb files. Install alien: apt-get install alien Converting an rpm package to Debian format: ... Read more

Solution for: fatal: open database /var/lib/postfix/smtpd_scache.db: File exists

If your mail server stops working (neither incoming nor outgoing email works) and you find the following error message in the mail.log file: fatal: open database /var/lib/postfix/smtpd_scache.db: File exists then the smtpd_scache.db might got corrupted. Postfix will recreate this file if it does not exist. So it can be removed to solve the issue: /etc/init.d/postfix ... Read more

Solution for dovecot error: /path/ is no longer mounted. If this is intentional, remove it with doveadm mount

Dovecot is watching the whole server filesystem for modifications and removed or added sub filesystems. If you get errors similar to this one on your server: Aug 30 09:10:23 server1 dovecot: master: Warning: /var/www/clients/client1/web1/log is no longer mounted. If this is intentional, remove it with doveadm mount  (the directory path may vary), then you can ... Read more

Incorrent Time on Windows/Linux Dual Boot System

If you work on a dual boot system you might experience that when you log off from Windows, onto Linux, and to Windows again, the time that is shown in the bottom right corner might be an hour or more off the actual time. This will correct once you refresh it by loading the time ... Read more