Correct. To be hit by this problem you need leaking sockets AND a client that opens and closes sockets rapidly. What I didn't write is that we had a "bind befor

Correct. To be hit by this problem you need leaking sockets AND a client that opens and closes sockets rapidly. What I didn't write is that we had a "bind before connect" on the client side, which means you could hit the CLOSE_WAIT _faster_ than after going through 30k+ sockets. Bind-before-connect sockets have random src port number, therefore depending on setup we hit the colliding socket in a thousand or so sockets, not in 30k+ sockets. Interesting comment on potential implications of automatically transitioning from CLOSE_WAIT.