I scanned 177 network elements using 4 scanner appliances and on a different network and locations. The scan last for 1hr and 30mins unfortunately the scan on one network makes the 2 core routers unreachable for 20mins. The scanning mode is set to normal.
Do you have any reported incidents similar to mine? btw there are 79 network elements behind the 2 core switches only 50 were scanned successfuly, router model is Cisco 4507R. These core routers were not included on the scan but they are the only route available to reach swiches inside the target network.
To add up, 2 core routers have high latency during the start of the scan, 70% of packets were lost, but looking on the graph of core routers going two the target network we havent seen any traffic at all.
Please advise if qualys can put down this type of router for a VA scan of 50 IP's at the same time.