systemd application firewalls by example
How to restrict Linux services’ network traffic with per-service systemd firewall rules. Enhance security by only allowing required network access.
Linux
What’s with cp --reflink: failed to clone: Invalid argument?
What would case a file-cloning attempt using the copy command to return “invalid argument”? It can be hard to identify the underlying issue.
How to resize ZRAM (compressed swap) managed by systemd/zram-generator
zram-generator’s default configuration uses 50% of RAM or 8 GB. You may want to increasing these limits if you’re throttled by low memory or swap performance.
TeamViewer RPM repo left door open for malicious packages
A configuration error made the TeamViewer RPM repository vulnerable to an attacker-in-the-middle substituting TeamViewer with its own GPG keys and software.
KMail account trouble
I’ve always wanted to use KMail. However, I always run into problems trying to use it. Unfortunately, this time was no different than my past experiences.
Linux on Lenovo ThinkPad T14: great except the webcam/mic
Lenovo continues its tradition of excellent Linux hardware support on the ThinkPad T14. Except minor issues with the built-in webcams and microphone.
Fix Linux suspend on low battery and prolong your battery life
How to troubleshot and fix issues with laptops not suspending on critically under low battery conditions. As a bonus, learn how to prolong your battery life.
Can Linux hibernate into tmpfs?
Hibernation requires that you can swap data out of volatile memory into something that will persist through a power cycle. A tmpfs in RAM isn’t the best option.
How to enable hibernation on Fedora Linux
Configure Fedora Workstation’s boot environment to support system hibernation/suspend-to-disk. Lets you power-off your computer and resume your work later.
How to auto-lock your computer on a schedule (e.g. at bedtime)
Automatically lock your computer screen at certain hours (such as your break or bedtime.) Instructions for Mac, Windows, and Linux computers.
How I recovered a lost email from my email client’s memory
A bug caused 30 minutes of work on an email to disappear. However, I was able to recover it by poking around in the process memory using gdb/gcore. Here’s how.
Limit the impact of a security intrusion with systemd directives
OpenSMTPD recently had a critical remote code execution vulnerability. I look at how you can limit impact with systemd-service security directives.