Posts
Page 60 of 72
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The Firewall Rule Order That's Breaking Your Setup
Firewall rules are evaluated top-down, first match wins. One misplaced ALLOW rule above your denials silently defeats all your security. Here's the fix.
5 min read -
Sticky Bit, Setuid, Setgid: Linux Special Permissions Explained
Understand sticky bit, setuid, and setgid: what they do, how to set them, security implications, and real-world use cases.
· Updated:6 min read -
Is fail2ban Actually Working? Here's How to Check
Verify fail2ban is protecting you: check jails, test bans, monitor logs, common misconfiguration, and unban IPs when needed.
6 min read -
Diagnosing Slow Linux Boot with systemd-analyze
Your Linux box takes forever to boot? systemd-analyze shows exactly which services drag it down. Read blame, critical-chain, plot, and fix the slow ones.
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Docker CMD vs ENTRYPOINT: The Final Answer
CMD and ENTRYPOINT work together rather than competing. Exec form vs shell form, the full behavior matrix, the combo pattern, and the debug override.
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SSHFS: Ditch SCP & Access Remote Files
SSHFS mounts remote filesystems over SSH so you can browse and edit files locally, faster than scp for interactive work.
· Updated:16 min read -
How to Actually Read `systemctl status` Output
systemctl status packs a lot into 12 lines. What Loaded, Active, Invocation, Main PID, Tasks, and the CGroup tree each tell you when a service misbehaves.
· Updated:7 min read -
SSH Agent Forwarding: How It Works
Understand SSH agent forwarding security risks. When it's safe (almost never), and better alternatives like ProxyJump for jump hosts.
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Is Your Linux Server Destroying Its SSD?
Default mount options and journald settings burn SSD write endurance. Check health with smartctl, mount noatime, move logs to tmpfs, find the real writer.
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Docker Compose Profiles: Run Only What You Need
Profiles let you conditionally start services in Compose. Perfect for dev vs prod service splits without multiple files.
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journalctl Queries Every Sysadmin Needs
Essential journalctl commands: -u, -f, --since, -p, -k, -b, --no-pager, JSON output. The queries you need on a broken server at 2 AM.
· Updated:6 min read -
Why Your SSH Connection Keeps Dropping
Fix SSH timeouts: ServerAliveInterval, ServerAliveCountMax, ClientAliveInterval. Understand NAT, firewalls, and TCP keepalive.
5 min read
