i'm trying to determine the ip of the network switch several linux boxes are plugged into. Background: i need to know in which physical port they're plugged in, so the machines automatically detect their 'spatial placing' (Since a certain port is hard-wired to a specific location). The port detection itself is done via snmp, which works quite well, but obviously i need the ip of the switch.
What i'm doing at the moment is: run nmap (meh...) with just ping scan on the whole subnet (or scanning for telnet, since the switch has this port open) and afterwards check the arp cache and retrieve the ip by checking against the mac address, since i know what manufacturer part to look for.
Question: Is there some easier way (avoiding nmap), i already tried arp broadcasting, but that doesn't seem to give me an arp cache entry for the switch. The switch in question is an IGS-801M from Planet Technology (http://www.planet.com.tw/en/product/product.php?id=25685), the (six) devices are plugged in directly, nothing network'ish between them. The switch gets his ip assign via dhcp or even auto assigned (169.xxx), static ip is no option. I also tried stuff like traceroute and hoping the switch would show up as a hop, but since it just (quietly) forwards stuff to the gateway it won't show up. Any ideas?