TCP port reuse results in a lower TCP Sequence number

Issue

• When an ephemeral port is reused, the kernel generates a lower TCP sequence number compared to the previous connection. Under normal conditions, I would expect a higher initial sequence number, especially since the remote TCP peer does not support TCP timestamps and therefore drops the SYN packet.
• TCP connection on the same tuple/quadruplet as a previous connection results in an ISN (Initial Sequence Number) which unexpectedly goes backwards, resulting in the remote listener rejecting the packet because of the TIME-WAIT socket on the listener. The TCP RFC says that if the ISN of a new connection attempt is larger then the port can be legally reused.