Detecting static routes in a network

A detection mechanism is disclosed for identifying peers transmitting network traffic towards a cloud provider using routing prefixes that were not advertised for that peer. Once detected, an alarm condition can occur and the peer notified to remove any static route configurations. In one embodiment, a collector server computer can be used to acquire routing prefixes advertised to a peer. A second server computer can be used to obtain network traffic received from the peer. A comparison can then be made between the advertised prefixes and the network traffic being received. If network traffic is being received for unadvertised prefixes, then an alarm condition can occur. The detection mechanism can regularly inspect active traffic flows against BGP route advertisements at fixed intervals. For peers that are identified that are not in compliance with route advertisements, the alarm condition can occur for follow-up remediation.