What is the definition of an Enode ID or Enode URI? What is it used for and how is it made?
Expanding on Hudson Jameson's answer: "The hexadecimal node ID is encoded in the username portion of the URL"
The username portion is a 512-bit public key that is used to verify communication came from a particular node on the network.
More about the RLPx protocol used can be found here.
Main parts of that:
An enode is a way to describe an Ethereum node in the form of a URI.
The hexadecimal node ID is encoded in the username portion of the URL, separated from the host by an @ sign. The hostname can only be given as an IP address, DNS domain names are not allowed. The port in the host name section is the TCP listening port. If the TCP and UDP (discovery) ports differ, the UDP port is specified as query parameter "discport".
In the following example, the node URL describes a node with IP address
The enode uri scheme is used by the Node discovery protocol and can be used in the