Methods and systems are described for sharing information for detecting an idle TCP connection. In one aspect, a second node receives a packet in a TCP connection. A header in the packet is detected identifying metadata for a period, detectable by a first node, during which no packet including data is received in the connection by the first node. The second node modifies a timeout associated with the connection based on the metadata. In another aspect, a first node receives information for detecting a period during which no packet including data sent in the TCP connection by a second node is received by the first node. A packet is generated including a header identifying metadata for the period based on the information, and sent to the second node. The period is detected based on the information. The connection is deactivated in response to detecting the period.