What Is a VPN?
a VPN — a Virtual Private Network — an encrypted tunnel across an untrusted network (like the internet) that makes remote devices or sites behave as if privately connected.
How it works
Site-to-site VPNs (typically IPsec) link office networks over the internet, replacing costly leased lines. Remote-access VPNs (SSL/TLS or IPsec clients) let individual users reach the office securely from anywhere. Encryption protects confidentiality; authentication ensures only trusted endpoints join.
Why it matters
VPNs appear in CCNA security topics and everywhere in real jobs — from configuring site-to-site IPsec (a CCNP ENARSI skill via DMVPN too) to CyberOps analysing VPN logs for anomalous logins.
Frequently asked questions
What does a VPN protect?
The confidentiality and integrity of traffic crossing untrusted networks — outsiders see only encrypted data between endpoints.
What is the difference between site-to-site and remote-access VPN?
Site-to-site permanently links whole networks (router to router); remote-access connects individual user devices on demand.
Does a VPN make you anonymous?
Not truly — it hides traffic from the local network and shifts your visible address, but the VPN provider and destination services still see activity.
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