Network & Security

NAT, proxies, VPNs, IP spoofing, reputation

• Proxies, VPNs and NAT: How Your IP Appears How proxies, VPNs and NAT change the IP a website sees, and what an IP can and cannot tell about you.
• How to Hide My IP Address (VPN, Proxy, Tor) The realistic ways to hide or change your public IP — VPNs, proxies and Tor — what each does, their trade-offs, and what hiding your IP does and does not protect.
• What Can Someone Find From My IP Address? What an IP address actually reveals — approximate location, ISP and network — and what it does not, such as your name, exact address or browsing history.
• How the SSL/TLS Certificate Chain Works Understand the chain of trust from a leaf certificate through intermediates to a root CA, why the order matters, and how to fix "incomplete chain" errors.
• How to Check SSL Certificate Expiry (and Never Get Caught Out) Commands and habits to check TLS certificate expiry dates from the CLI and in monitoring, plus why 30 days is the magic number.
• TLS Versions Explained: 1.0 to 1.3 A practical comparison of TLS 1.0, 1.1, 1.2 and 1.3 — what changed, what is deprecated, and what you should require today.
• ACME and Let's Encrypt: Automatic Certificates How the ACME protocol issues and renews TLS certificates automatically, the HTTP-01 vs DNS-01 challenges, and when a paid certificate still makes sense.
• HTTP Security Headers Explained What HSTS, CSP, X-Frame-Options, X-Content-Type-Options, Referrer-Policy and Permissions-Policy do, with recommended values.
• X-Forwarded-For: Getting the Real Client IP Behind a Proxy How X-Forwarded-For works behind reverse proxies and CDNs, why trusting it blindly is a security hole, and how to read it correctly.
• CGNAT Explained: Why You Share a Public IP Carrier-Grade NAT lets ISPs put many subscribers behind one public IPv4 address. Here is how it works and what it breaks.
• Certificate Transparency (CT) and SCTs Explained How Certificate Transparency logs make every TLS certificate publicly auditable, what an SCT is, and how to search CT logs for your domain.
• Certificate Revocation: OCSP, CRL and Stapling How TLS certificates are revoked and checked — CRLs, OCSP, OCSP stapling and Must-Staple — and why revocation is harder than it looks.
• Can Someone Track Me by My IP Address? What your IP address actually reveals, what it does not, and practical steps if you want to reduce what others can see.