Grr. My previous email was cut off. The upshot is that the switch does not have a default route (it's a switch, after all, not a router) so it cannot respond to the icmp request. Is it possible to set a default router for the interface (in this case, vlan 7) that has the IP address assigned to it?
J. Johnson wrote: > Priscilla Oppenheimer wrote: > >> >> You gotta get it to stop doing that! ;-) Seriously, why doesn't the Linux >> router-on-a-stick know that the destination is local, on VLAN 7? >> Shouldn't it know not to send this packet to another router? It should >> just ARP for the destination and send the packet, perhaps tagged for VLAN >> 7. > > I've tried it both ways, with the address in the linux router's table, and > with it redirecting to the 3600. I'll put 10.0.0.6 back in the linux > router's table and sniff ... Yep, it behaves similarly (but with the extra > routing hop to the 3600 removed.) Now, the icmp request goes from the box > on oreilly.net up vlan5 through the 2950 switch to the linux router, back > out vlan7 to the switch, and the switch does an arp request out vlan 7 for > the originating box. Vlan 7 doesn't include oreilly.net, so the arp > request goes unanswered. > > > >> VLAN 7! ;-) Of course, it is in fact seeing that IP address coming in on >> VLAN 7, so maybe it assumes that's where the address is really located >> and ARPs to there. The source IP address has been remaining the same >> throughout all this, though the MAC addresses have been changing. It sees >> the source IP address for oreilly come in on VLAN 7. Could that be >> confusing it? I don't think it should, but it might. > > Thank you - of course the switch is > confused. Think of how ping usually works: > > BOX A --- ROUTER B --- ... --- ROUTER Y --- BOX Z > > A pings Z, but since it doesn't know Z's MAC address it sends the request > to > a router, which is B. A knows how to do this because it has a routing > table, or it knows a default router. B and all intervening routers do the > same until the packet gets to Y. Now Y has to do the same to get the > response back to A. ---> However, if Z doesn't know where A is, it also > has to send the response to a router. > > James > Nondisclosure violations to [EMAIL PROTECTED] Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=64282&t=63789 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
