Priscilla Oppenheimer wrote: > > henry bb wrote: > > > > today I already know why 2500 can ping 88.1.77.1 because > > It doesn't make sense that the 2500 can ping all the way to the > 3550 Ethernet interface based on the minimal information that > you told us before. You must be doing routing. It has nothing > to do with Proxy ARP, though. Maybe you have on-demand routing > or something.
Ignore that part of the message. I just noticed the inconsistent subnet masks. Of course, it works. The router in the middle knows how to get to each subnet using the /24 mask. The router on the left knows that all of the larger subnet is out its serial interface. It's a bug to have the two routers on the left using a different subnet mask to refer to the WAN subnet, by the way. Why worry about whether it works and how it works at all if you're using a buggy configuraton? :-) Priscilla > > > proxy-arp doesn't function on serial interface. > > so what's the real function of proxy-arp on serial interface > ? > > Proxy ARP has no meaning on a serial interface. ARP has no > meaning on a serial interface, (unless you're referring to > Frame Relay's Inverse ARP, which is a different story. It finds > the IP address when the DLCI is known.) > > Serial interfaces don't have MAC addresses. They don't connect > devices that have MAC addresses. ARP finds the MAC address when > the IP address is known. It's meaningless on a serial interface. > > If you configure Proxy ARP on an Ethernet interface, the router > could respond to ARP requests on its Ethernet side on behalf of > devices on its other side, (across the serial link in this > case), assuming the router knows that it can get to those > devices. That's the definition of Proxy ARP. > > > Does it work when bridge on the serial interface ? > > If bridge on serial interface,how ios transfer arp ? I think > > there isn't mac address on serial interface . Is there some > > encapusation to packet the mac and transfer the lan frame > > through serial interface ? > > If you were doing bridging, then the router interfaces would be > passing all broadcasts, without any knowledge of what they were > passing. So Ethernet devices could theoretically ARP through a > bridged network that included WAN links. The encapsulation > would be whatever was configured for the WAN links. It wouldn't > matter. Bridging is transparent. > > I've never heard of anyone doing that and there might be some > gotchas, but I think it would work. The ARP data has enough > info in it for it to work. It doesn't care about the > data-link-layer header that is used to transfer the request or > reply. > > Priscilla > > > > > regards > > Henry > > Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=71155&t=71113 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
