Security on Du Song's Tech Bloghttps://blog.dusong.ai/tags/security/Recent content in Security on Du Song's Tech BlogHugoen-usFri, 20 Mar 2026 16:45:00 +0800Practical fail2ban Configuration for SSH Protectionhttps://blog.dusong.ai/posts/fail2ban-ssh/Fri, 20 Mar 2026 16:45:00 +0800https://blog.dusong.ai/posts/fail2ban-ssh/How to configure fail2ban to protect SSH from brute-force attacks, with practical tips on tuning ban times and handling false positives.Automating Let's Encrypt Certificates with acme.shhttps://blog.dusong.ai/posts/acme-sh-letsencrypt/Sun, 01 Mar 2026 09:15:00 +0800https://blog.dusong.ai/posts/acme-sh-letsencrypt/Setting up automated SSL certificate issuance and renewal using acme.sh with DNS-01 validation via Cloudflare.