Flow Visualizer TCP Trace graph flags
          The following table describes each of the flags in the TCP Trace graph of the Flow Visualizer.
          | Client | Server | Flag | Description | 
|---|---|---|---|
|  | yes |  | TCP PUSH flag set (appear as a diamond, rather than an arrowhead, and do not have a text label) | 
| yes | yes | FIN  | TCP FIN flag set (shows a square, rather than an arrowhead)  | 
| yes | yes | SYN  | TCP SYN flag set (shows a diamond, rather than an arrowhead)  | 
| yes | yes | U  | TCP Urgent flag set | 
| yes |  | RST_IN  | TCP RST flag set in ACK packet from client | 
|  | yes | RST_OUT  | TCP RST flag set in packet from server | 
|  | yes | R  | Retransmitted data (at least one byte of SEQ overlaps) | 
|  | yes | O  | Out of sequence data | 
| yes |  | Z  | ACK packet with a zero window | 
|  | yes | P  | Zero window probe | 
| yes | yes  | !  | The Expert identified an event for this packet | 
| yes | yes | HD  | Hardware Duplicate (also called IP Local Routing) | 
| yes |  | S  | Selective ACK (also shows a purple line, spanning the acknowledged sequence numbers) |