How to access Webmin behind a firewall using an SSH tunnel
At times your Webmin server might be behind a firewall and not accessible via port 10000. If you have SSH access to the server in
Security
How to generate a random password using the command line in Linux
The command below will generate a random password sequence for those times when you’re so tired of thinking of yet another random password: pwgen Reference
My emails stopped working – your system is blocking me – this is so annoying – I am a paying customer
Background From time to time email stops working out of the blue. This is especially pronounced if you have many accounts and all of them
How to impersonate another Linux user using SUDO
sudo -i -u mary You need to use the -i (login) option. Reference https://www.howtogeek.com/447906/how-to-control-sudo-access-on-linux
How to deal with ACMEv1 is deprecated and you can no longer get certificates from this endpoint. Please use the ACMEv2 endpoint
Whilst trying to renew a Let’s Encrypt certificate on an older CentOS server, you might experience the following: Cert is due for renewal, auto-renewing… Starting
How to never get phished
There are technical ways to look at any website and email to determine what the actual links are. Phishers are sophisticated criminals and try to
How to install chkrootkit on CentOS 7
chkrootkit is a tool that’s used to determine if a Unix server has been compromised. You can’t do yum install chkrootkit on CentOS so follow
Fail2ban Postfix SASL Troubleshooting
Background On some Virtualmin server you may find that Fail2ban is logging events, but soon realize that due to the amount of “already banned” messages
iptables cheat sheet
What is iptables? iptables is a powerful firewall utility for Linux that is often included with the operating system. Behind the scenes many firewalls also
How to check and remove IPs from fail2ban
Background Fail2ban is a really powerful utility and can help you out of a bind. The problem is the syntax – it’s changed and when