I would like to know how many IPs can an appliance scan? We plan on performing fully authenticated scans on a large network.
We have a limited time window in which to perform the scans so thus the design,applicance placement and total number of appliances is very important.
Scan performance is highly dependent upon the network conditions during the time of the scan. The QualysGuard scan engine will throttle performance settings based on network conditions.
That being said, this thread likely has the information that you're looking for, this document has a little information on bandwidth utilization, here are some statistics on pps that we've seen in the wild, and of course, you should review our document on scanning through firewalls.
Hope this helps,