A site-to-site VPN provides access from one network to another over the internet. It works by creating a secure, encrypted tunnel between two networks located at different sites. The tunnel acts as a direct link through which data can be securely transmitted.

The process involves establishing a gateway at each network end, effectively connecting entire networks rather than individual clients to a VPN server. The VPN gateway manages data encryption and decryption as it enters and exits the tunnel.

Data travels through the public internet within this tunnel. Encryption makes the data opaque to outsiders, appearing as unintelligible gibberish. Upon reaching the destination gateway, data is decrypted and transmitted to the receiving internal network.

This secure bridge allows seamless, secure information flow between networks. Resources can be shared as though they are on the same local network. [Palo Alto Networks]