Some poor WPS implementations will

Some poor WPS implementations will drop a
connection on the floor when an invalid pin is
supplied instead of responding with a NACK
message as the specs dictate. To account for
this, if an M5/M7 timeout is reached, it is
treated the same as a NACK by default. However, if it is known that the target AP
sends NACKS (most do), this feature can be
disabled to ensure better reliability. This option
is largely useless as Reaver will auto-detect if
an AP properly responds with NACKs or not: # reaver -i mon0 -b 00:01:02:03:04:05 -- nack While most APs don't care, sending an EAP
FAIL message to close out a WPS session is
sometimes necessary. By default this feature
is disabled, but can be enabled for those APs
that need it: # reaver -i mon0 -b 00:01:02:03:04:05 -- eap-terminate When 10 consecutive unexpected WPS errors
are encountered, a warning message will be
displayed. Since this may be a sign that the
AP is rate limiting pin attempts or simply being
overloaded, a sleep can be put in place that will
occur whenever these warning messages appear: # reaver -i mon0 -b 00:01:02:03:04:05 -- fail-wait=360