# TCP Flags

Transmission Control Protocol (TCP) Flags are control bits for [TCP](/glossary/t/tcp) messages. These flags indicate how packets should be handled or indicate connection states.

^ Flag ^ Description ^
| SYN | Synchronize sequence numbers. |
| ACK | Acknowledgment field is significant. |
| FIN | No more data from sender. |
| RST | Reset the connection. |
| URG | Urgent pointer field is significant. |
| PSH | Push function. |
| CWR | Congestion Window Reduced. |
| ECE | TCP peer is ECN capable. |