barmar@think.com (Barry Margolin) (03/12/91)
In article <9103111554.AA09237@hub.eng.wayne.edu> qureshi@WSU-ENG.ENG.WAYNE.EDU (Imran U. Qureshi 7-0108) writes: >2. I cleared the Cisco arp and tried to ping the X-terminal, the entry in >the arp cache related to the X-terminal comes back with same VAX MAC >address. This thing happens even if the X-Terminals are not on the network. Sounds like the VAX is sending proxy ARP responses for some reason. Perhaps its subnet mask isn't set properly, and it thinks the ARP requests are for a different subnet, and it thinks it is the router to that subnet. > Can the Cisco get MAC level addresses from HP9000 or from any other host >when X-terminals are not on the network? Any host can answer an ARP broadcast, whether or not the actual destination host is on the network. Many routers support proxy ARP, for the benefit of hosts that don't implement subnetting; the router responds to ARP requests for any host on one of its other interfaces, giving its own MAC address, whether or not the destination host actually exists. -- Barry Margolin, Thinking Machines Corp. barmar@think.com {uunet,harvard}!think!barmar