MAC Address Vendor Search This tool searches for the vendor belonging to a MAC address. Using the first six hex values, the search will return the vendor. You can also search in reverse by the vendor, showing all the MAC addresses that they own. This database is built from the IEEE records at ieee.org which is updated every quarter.
IP Subnet Calculator This tool allows for the calculation of IP subnets, showing the netmask, Cisco wildcard, network, number of hosts and broadcast addresses. This cgi script and a command line version are available from the author here.
More tools will be added as time allows.