Strange IPS warnings since today

Hello all,

since today the IPS has some strange detections and I receive periodically the notifications, until now approx. 130.

Unfortunately I can't figure out what the problem is.

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Subject: [GQDN Gateway][WARN-850] Intrusion Prevention Alert

Intrusion Prevention Alert

Details about the intrusion alert:

Message........: ICMP Microsoft remote unauthenticated DoS/bugcheck vulnerability
Details........: Snort ::
Time...........: 2012:05:21-16:02:07
Packet dropped.: no
Priority.......: medium
Classification.: Attempted Denial of Service
IP protocol....: 1 (ICMP)

Source IP address: ***.***.***.1 (gateway)
Source port: 0
Destination IP address: ***.***.***.201 (FQDN Server)
Destination port: 0
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System Version is 8.302.

I receive this notifacations for two server ***.***.***.200 and .201. Both servers are configured as DC and DNS.

Why the Astaro is initiating such requestes on Port 0?

Thoughts, comments, solutions are much appreciated.

Many thanks.

PSyc