Tag: security

SSH Hardening: Lock Down Remote Access Without Locking Yourself Out

Harden SSH properly: disable password auth, switch to Ed25519 keys, configure sshd_config, set up SSH certificates with step-ca, add 2FA, and configure ProxyJump for bastion hosts.

Vaultwarden vs Bitwarden: Own Your Passwords Before Someone Else Does

Why trust a cloud with your passwords? Compare Vaultwarden and Bitwarden self-hosted — lightweight vs full-stack, Docker setup, backups, and which one to actually run.

Linux Audit Log: What's Really Happening on Your Server

auditd logs every system call, file access, and command run on your Linux server. Learn ausearch, aureport, and how to write audit rules that catch it.

The sudoers Mistake Everyone Makes Once

Never edit /etc/sudoers directly. One syntax error locks everyone out. Use visudo, understand NOPASSWD risks.

Why Your TLS Certificate Isn't Trusted

Incomplete cert chains, wrong order, self-signed certs. How to diagnose trust failures with openssl s_client.

Certificate Expiry: Monitor Before the 3 AM Call

Certs expire silently. Check expiry with openssl, automate renewal checks with cron, get alerts before disaster.

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.

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.

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.

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.

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.

The umask You've Been Ignoring

Understand Linux umask: what it is, how 022 and 027 work, calculating file permissions, and why it matters for shared directories and security.