What is the remote endpoint of peer ABCDEFGH? Let me look.

Encrypt entire IP packet using peer ABCDEFGH's public key.

(Or if it's not for any configured peer, drop the packet.) When the interface sends a packet to a peer, it does the following: WireGuard associates tunnel IP addresses with public keys and remote endpoints. This interface acts as a tunnel interface. The specific WireGuard aspects of the interface are configured using the wg(8) tool. This network interface can then be configured normally using ifconfig(8) or ip-address(8), with routes for it added and removed using route(8) or ip-route(8), and so on with all the ordinary networking utilities. WireGuard works by adding a network interface (or multiple), like eth0 or wlan0, called wg0 (or wg1, wg2, wg3, etc). In contrast, it more mimics the model of SSH and Mosh both parties have each other's public keys, and then they're simply able to begin exchanging packets through the interface. All issues of key distribution and pushed configurations are out of scope of WireGuard these are issues much better left for other layers, lest we end up with the bloat of IKE or OpenVPN. You add a WireGuard interface, configure it with your private key and your peers' public keys, and then you send packets across it.

WireGuard securely encapsulates IP packets over UDP. If you intend to implement WireGuard for a new platform, please read the cross-platform notes. If you're interested in the internal inner workings, you might be interested in the brief summary of the protocol, or go more in depth by reading the technical whitepaper, which goes into more detail on the protocol, cryptography, and fundamentals. You then may progress to installation and reading the quickstart instructions on how to use it.

If you'd like a general conceptual overview of what WireGuard is about, read onward here. WireGuard is the result of a lengthy and thoroughly considered academic process, resulting in the technical whitepaper, an academic research paper which clearly defines the protocol and the intense considerations that went into each decision.

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