How can I determine the IP Address of the current master router in a VRRP scenario? This would be the IP Address I could use for SNMP queries to that router. The virtual IP Address can't be used for the SNMP queries. I've read that if I can ping the VRRP's virtual IP address, this is probably the IP Address Owner, and I can use that IP Address for SNMP queries. But if the IP Address Owner is down, how can I figure out which router is the master? It seems all the necessary information is in the VRRP-MIB, but I don't have an IP Address to reach that MIB.
Or is it impossible to determine which router is the current master? I suppose if you had the IP Addresses of all the members of the VRRP you could query the VRRP-MIBs of them to figure out who is the master. But I'm assuming I don't have those IP Addresses.
there doesnt need to be any VRRP actual "owner" of the address (ie 1 configured with priority 255).
"owner" setting is not always used, since it can cause problems in switchover with some layer 2 switches.
This would be the IP Address I could use for SNMP
it would only work if the owner was operational.... so polling would break whenever that address was down.
The virtual IP Address can't be used for the
the RFC specifies only the owner responds to "ping", but that varies with implementation (no idea what the cisco does, but Nortel kit lets you allow it since stopping ping replies breaks dead gateway detection on some clients).
you can also vary the config. see:
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can always see which address is acting as the gateway from the command line, but because of the way VRRP works a device may not know which other routers are available as backups.
1 point - arre you sure your box is running VRRP and not HSRP or GLBP? - Cisco always teaches HSRP, and GLBP is better in some ways than either....
anyway - it sounds like you are trying to find the topology without any network maps.
a better fix is either to find a router elsewhere and discover other routers via walking the routing table entries, or some sort of "helper" system such as CDP.
But none of these methods are guaranteed, making them work is complicated, and in many networks your discovery will be blocked - eg by security filters.
anyway - for polling, dont you want to find the loopback addresses on each router, rather than 1 of the interfaces?
it is in the VRRP packets on the wire (since the routers have to know), and the Cisco command line should tell you on any box participating in that particular VRRP group on that LAN.
what you really need is documentation, or a login on the router (which presupposes a console connection or an IP address). Welcome to yet another circular logic trap / problem in network management....
or if you have a network analyser on the segment, you can look at the source IPs in the VRRP multicasts.
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