groups:
  - id: server
    prefix: server
    type: attribute_group
    brief: >
      These attributes may be used to describe the server in a connection-based network interaction
      where there is one side that initiates the connection (the client is the side that initiates the connection).
      This covers all TCP network interactions since TCP is connection-based and one side initiates the
      connection (an exception is made for peer-to-peer communication over TCP where the "user-facing" surface of the
      protocol / API does not expose a clear notion of client and server).
      This also covers UDP network interactions where one side initiates the interaction, e.g. QUIC (HTTP/3) and DNS.
    attributes:
      - id: address
        type: string
        brief: 'Logical server hostname, matches server FQDN if available, and IP or socket address if FQDN is not known.'
        examples: ['example.com']
      - id: port
        type: int
        brief: 'Logical server port number'
        examples: [80, 8080, 443]
      - id: socket.domain
        type: string
        brief: The domain name of an immediate peer.
        examples: ['proxy.example.com']
        note: Typically observed from the client side, and represents a proxy or other intermediary domain name.
        requirement_level:
          recommended: If different than `server.address`.
      - id: socket.address
        type: string
        brief: >
          Physical server IP address or Unix socket address. If set from the client, should simply use the socket's peer address, and not attempt to find any actual server IP (i.e., if set from
          client, this may represent some proxy server instead of the logical server).
        examples: ['10.5.3.2']
        requirement_level:
          recommended: If different than `server.address`.
      - id: socket.port
        type: int
        brief: Physical server port.
        examples: [16456]
        requirement_level:
          recommended: If different than `server.port`.