On 3/8/2011 11:11 PM, Atom Powers wrote: > I haven't seen this before and it's causing me all kinds of headache. > > I have a Cisco 3560G with > * some local VLAN interfaces and RIP2 > * a router-on-a-stick and RIP2 (on a trunk port) > * a Xen server on a trunk port (VMs can be on one or more of three > different VLANs) > * some hosts on access ports > > RTR is the Router-on-a-stick > HostA is a Virtual Machine on the Xen server. > HostB is a physical server on an access port. > HostA and HostB are on the same subnet. > RTR is the default gateway for the subnet of HostA and HostB. > RTR can ping both HostA and HostB > HostA can ping other hosts on access ports and hosts on other networks. > HostB can ping other hosts that are VMs and hosts on other networks. > > HostA can NOT ping HostB (or other VMs on that network) and HostB can > NOT ping HostA (or other physical servers on that network). > > I can see ARP requests on RTR from both HostA and HostB, but the hosts > themselves never see the ARP requests from the other host. > > If I manually add the hosts to each other's ARP table then HostA can > ping HostB and visa versa. > > So ... What the heck is going on? Why isn't the switch forwarding the > ARP requests to all ports on the same VLAN? > > I think the trouble started when I enabled RIP2 on the switch. But > neither I nor Google can figure out why that would matter or how to > fix it. > I did a google search and saw a few things about LAPs and trunk vs access ports. I don't know if you've seen this one: https://learningnetwork.cisco.com/thread/7715
can the machine that is acting as the vm container for hostA reach other machines or does it also have the same intra-vlan restrictions (trying to eliminate your VM stuff as a problem). You could try to turn on port mirroring on the switch and put tshark or equivalent on there and see what packets are actually going on that vlan. _______________________________________________ Tech mailing list [email protected] https://lists.lopsa.org/cgi-bin/mailman/listinfo/tech This list provided by the League of Professional System Administrators http://lopsa.org/
