Source Attributes

These attributes may be used to describe the sender of a network exchange/packet. These should be used when there is no client/server relationship between the two sides, or when that relationship is unknown. This covers low-level network interactions (e.g. packet tracing) where you don’t know if there was a connection or which side initiated it. This also covers unidirectional UDP flows and peer-to-peer communication where the “user-facing” surface of the protocol / API does not expose a clear notion of client and server.

Attribute	Type	Description	Examples	Stability
source.address	string	Source address - domain name if available without reverse DNS lookup; otherwise, IP address or Unix domain socket name. [1]	source.example.com; 10.1.2.80; /tmp/my.sock
source.port	int	Source port number	3389; 2888

[1]: When observed from the destination side, and when communicating through an intermediary, source.address SHOULD represent the source address behind any intermediaries, for example proxies, if it’s available.