Cisco 2611 router running IOS 12.1(6.5), possibly an interim release, allows remote attackers to cause a denial of service via port scans such as (1) scanning all ports on a single host and (2) scanning a network of hosts for a single open port through the router. NOTE: the vendor could not reproduce this issue, saying that the original reporter was using an interim release of the software.
http://www.securityfocus.com/bid/4947
http://www.iss.net/security_center/static/9281.php
http://archives.neohapsis.com/archives/bugtraq/2002-06/0050.html
http://archives.neohapsis.com/archives/bugtraq/2002-06/0027.html