source: http://www.securityfocus.com/bid/6059/info

The Cisco AS5350 Universal Gateway is reported to be prone to a denial of service condition. It is possible to cause this condition by portscanning a vulnerable device.

This issue was reported for Cisco AS5350 devices running Cisco IOS release 12.2(11)T. Other firmware and devices may also be affected.

There are conflicting reports regarding the existence of this vulnerability. One source states that this condition reportedly does not occur if there are no Access Control Lists (ACL) applied on the device and also mentions that this may be related to a known SSH bug. Other sources have indicated that the issue may be related to a configuration problem. 

nmap -Tinsane -p 1-65535 <target>