https://mathscantor.github.io/tags/vpn/ Recent content in Vpn on Mathscantor's Cybersecurity Blog Hugo en-us <a href="https://creativecommons.org/licenses/by-nc/4.0/" target="_blank" rel="noopener">CC BY-NC 4.0</a> Mon, 14 Sep 2026 09:34:00 +0800 https://mathscantor.github.io/posts/vr-on-ipsec-vpn/part-1-first-peek-into-the-rabbit-hole/ Mon, 14 Sep 2026 09:34:00 +0800 https://mathscantor.github.io/posts/vr-on-ipsec-vpn/part-1-first-peek-into-the-rabbit-hole/ <h2 id="1-background">1. Background</h2> <h3 id="11-what-is-ipsec">1.1 What is IPsec?</h3> <p>IPsec (Internet Protocol Security) is a suite of protocols used to secure IP communications over untrusted networks such as the Internet. It provides:</p> <ul> <li> <p><strong>Confidentiality</strong> &ndash; encryption prevents eavesdropping on traffic.</p> </li> <li> <p><strong>Integrity</strong> &ndash; tamper detection ensures packets have not been modified in transit.</p> </li> <li> <p><strong>Authentication</strong> &ndash; both peers verify each other&rsquo;s identity before exchanging data.</p> </li> <li> <p><strong>Anti-replay protection</strong> &ndash; sequence numbers prevent an attacker from capturing and replaying legitimate packets.</p>