Richard, when examining the subnet mask of a client, one has to understand if the mask was manually entered or was given to the client by a DHCP server. I agree with you that the subnet data should be derived from a suitable source such a router docs or DHCP definitions. But if clients are manually configured we have seen many times that incorrect data could be entered into the IP configuration. At times these clients even seem to work with incorrect configs. I would advise that clients no be used at all for determining subnet data. That being said, I collect this information from my clients and compare it to the subnets defined in QIP to find those inconsistencies in the ip environment.
