
Scan Always
This option instructs the scanner main program to try to connect to the host
if ping fails. (Ping is the usual test to see if a machine is connected.) The
scanner sends a packet to see if the machine is "alive." Sometimes the scanned
network blocks the ICMP (ping) packets. This can lead the scanner to assume that
there is nothing out there to answer. When this option is in effect, The
scanner attempts to scan for TCP ports even when the first ping test fails.
This scanning method is thorough but also more time-consuming. If the network
that is being scanned is not blocking ICMP packets, turning this option on
unnecessarily increases the time it takes to scan a network. To test to see if an
ICMP packet is allowed through the network, try to ping a host that is known to
be alive. If ping reports that the host is alive, turn off the Scan Always
option to save time.
Note: Enabling this option can cause Windows NT to appear to hang. See