Dear Customer,
A standard change on the internal Firewall in our DC3HAM colocation triggered a high availability problem because of a years old unnoticed configuration error. This error resulted in the intrusion prevention blocking hosts that should not have been blocked, including DNS. These cascading error unfortunately took a while to cleanup.
A complete review of the firewall rules is already underway by 2 people independently.
Best regards
Your MCON Managed Service Team