Summary Denial of service overload attempt.
Details
A large number of ICMP port-unreachable frames have been sent to a single IP address. The system and network may become unresponsive.
This often occurs as the result of an attack by a UDP-port scanner, which is scanning unsupported ports. This also may be a denial of service attack in which the source IP address is spoofed. When spoofing occurs, the real source of the attack may be hard to determine.
This may also occur as the result of a system or network misconfiguration. Sometimes, the system labelled as the intruder is trying to repetitively access a service which is unavailable.
