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Gratuitous ARP Requests are not sent upon cluster fail-over for IP addresses configured in the $FWDIR/conf/local.arp file, if those IP addresses and Cluster VIP address are on different subnets
Symptoms
  • Gratuitous ARP Request packets (GARP) are not sent upon cluster fail-over for IP addresses configured in the $FWDIR/conf/local.arp file (per sk30197), if those IP addresses and Cluster VIP address are on different subnets.

  • Example topology:

    Internal Network --- [Cluster] --- External Network

    • IP addresses of Internal Hosts that are advertized on External Network are 172.30.10.X/24
    • Cluster VIP address on External Network is 192.168.10.1/24

    Cluster debug ('fw ctl debug -m cluster + if mac') shows failures similar to the following:

    ;FW-1: fwha_send_gratuitous_arp: do send arp, ifn = 10, if_exists = 1, is_bond_slave = 0, fwha_cluster_cpips[i]=1.10.168.192, fwha_cluster_cpip_netmasks[i]=0.255.255.255, IF_ETHER(i)=00:50:56:AA:4B:07, IF_NETMASK(i)=0.255.255.255;
    ;fwha_send_gratuitous_arp: FWHA_SUBNET_BCAST(fwha_cluster_cpips[i], fwha_cluster_cpip_netmasks[i])=255.10.168.192;
    ;fwha_send_gratuitous_arp: FWHA_SUBNET_BCAST(_htonl(ip_addr), fwha_cluster_cpip_netmasks[i])=255.10.30.172;
    ;FW-1: fwha_send_gratuitous_arp: couldn't find a local interface for mac 00:50:56:AA:4B:07;
    
Cause

By the current design, Gratuitous ARP Request packets (GARP) are sent only for IP addresses (configured in the $FWDIR/conf/local.arp file per sk30197) from the same subnet as the Cluster VIP address.


Solution
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