Quote:
It should also be noted that Nmap has been known to crash certain
poorly written applications, TCP/IP stacks, and even operating systems.
Nmap should never be run against mission critical systems unless you
are prepared to suffer downtime. We acknowledge here that Nmap may
crash your systems or networks and we disclaim all liability for any
damage or problems Nmap could cause.
Because of the slight risk of crashes and because a few black hats like
to use Nmap for reconnaissance prior to attacking systems, there are
administrators who become upset and may complain when their system is
scanned. Thus, it is often advisable to request permission before
doing even a light scan of a network.
After doing a google search on "nmap crashes" and sorting through pages and pages of hits I found numerous complaints of problems scanning some Cisco equipment, Solaris, VPNs, and more. Most were older complaints, but then again I didn't get even close to searching all the hits.