What is marked by the connection-state=established matcher?

The matcher "connection-state=established" is used to identify packets that belong to an existing connection, confirming that they are part of an ongoing communication session, such as those involved in TCP. When a packet is marked as "established," it indicates that it is a packet that is part of a two-way communication pathway that has already been established, typically in response to a previous packet from the opposite direction—like a reply packet in the context of TCP connections.

In contrast, the other options describe different states in the connection lifecycle. A packet related to an existing connection would typically use the "related" matcher, while a packet that does not match any known connection would not be considered established at all. Additionally, a packet that initiates a new connection would be marked as such and reflect a state of being "new" rather than "established." Therefore, identifying a packet as "connection-state=established" specifically denotes that it is part of an established interaction, making the first choice the accurate one.