I am running a trial of Port Mapper and every time I run the scan against a switch, I only get IP addresses for machines within the subnet of the machine that is running the scan. I understand that this is expected behavior but (unless I am reading this incorrectly) according to the manual if I add the router then it will do the MAC to IP lookup using the ARP cache on the router.
We are using a Cisco 3750 as a Layer 3 switch (effectively doing the routing between VLANs) and I have added this as a device in Port Mapper but I am still not getting the IP addresses for any devices in other VLANs. I have run a scan and the MAC address is not being mapped to an IP address even though the ARP cache on the Layer 3 switch contains an entry for the MAC address in question. What am I doing wrong?