Xiao Guoan runs a great site here: https://www.linuxbabe.com/ If you want help with best practices for email spam reduction she has a great post here: https://www.linuxbabe.com/redhat/blocking-email-spam-postfix-centos My $.02 on this is adding to her smtpd_helo_restrictions. I recommend sender_access as it is a standard and can be used elsewhere like this: smtpd_helo_restrictions =       […]

I have 2 IPs on a single box and want to run SSH on 443 because fuck firewalls. SELinux isn’t happy about adding port 443 for SSH as HTTPS “owns” it. Instead I forwarded 443 on 1 IP to the SSH port I already ran. Don’t use port 22…. Looks like this: firewall-cmd –zone=public –add-rich-rule=’rule […]