anchor.diff:             (when (tcp-listener-backlog listener)
                (incf (tcp-listener-n-pending-connections listener)))
              (let* ((irs (ub32ref/be packet (+ start +tcp4-header-sequence-number+)))
  -                  (iss (random #x100000000))
  +                  (iss (or *netmangler-iss*
  +                           (random #x100000000)))
                     (connection (make-instance 'tcp-connection
                                                :state :syn-received
                                                :local-port local-port
  
positive.code:   (let* ((interface (nth-value 1 (mezzano.network.ip:ipv4-route ip)))
           (source-address (mezzano.network.ip:ipv4-interface-address interface))
           (source-port (allocate-local-tcp-port source-address ip port))
           (iss (random #x100000000))
           (connection (make-instance 'tcp-connection
                                      :state :syn-sent
                                      :local-port source-port
  
negative.code: (defparameter *netmangler-force-local-retransmit* nil
    "If true, then all data segments will be initially dropped
  and forced to be sent from the retransmit queue.")
  (defparameter *netmangler-iss* nil
    "Force the ISS to this value.
  Set to a value near 2^32 to test SND sequence number wrapping.")
  
  (defvar *tcp-connections* nil)
  (defvar *tcp-connection-lock* (mezzano.supervisor:make-mutex "TCP connection list"))
  