Partial external connectivity issues in RZOB

Incident Report for Flying Circus

Resolved

A process on a customer machine in RZOB, our public datacentre, generated an unusually large amount of otherwise legitimate traffic which was erroneously classified as a denial of service attack by our uplink provider. In response, an attack mitigation was triggered which throttled outgoing connections from the public source address down to a low speed. As the customer machine did not have its own public IP addresses and connected to external services through a NAT gateway, this resulted in the NAT gateway being throttled, which also affected other customers' machines which used the NAT gateway.

We stopped the process generating excess traffic and escalated to our uplink provider in order to clear the throttling affecting the NAT gateway.

Posted Feb 25, 2026 - 17:00 CET