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I have a nexus N5K-C5672UP as core layer 3 for our VLAN's. VLAN 601 on core 2 is secondary vrrp:

core 02:

core02# show vrrp
  Interface  VR IpVersion Pri   Time Pre State   VR IP addr
---------------------------------------------------------------
    Vlan601   1   IPV4     90    1 s  Y  Backup   172.17.1.1

    interface Vlan601
  no shutdown
  ip address 172.19.1.3/24
  vrrp 1
    priority 90
    address 172.19.1.1
    no shutdown

core01:

core01# show vrrp
  Interface  VR IpVersion Pri   Time Pre State   VR IP addr
---------------------------------------------------------------
    Vlan601   1   IPV4    110    1 s  Y  Master   172.19.1.1

 interface Vlan601
  no shutdown
  ip address 172.19.1.2/24
  vrrp 1
    priority 110
    address 172.19.1.1
   no shutdown

I have a an esxi host - with linux trunked to core02. I would expect he would not use the layer 3 interface of vlan 601 from core02 - but that he would use the layer 3 interface of core01. However a traceroute shows he uses the secondary vrrp interface IP as his first hop:

using vrrp backup IP as first hop:

user@host:~$ ssh host "traceroute anotherhost"
traceroute to anotherhost (172.19.1.xx), 30 hops max, 60 byte packets
 1  172.19.1.3 (172.19.1.3)  0.648 ms  0.808 ms  0.951 ms # vrrp backup IP 
2  172.19.15.2 (172.19.15.2)  1.082 ms  1.180 ms  1.105 ms

Am I wrong here - but shouldn't he be using layer 3 here and hitting the primary vrrp even though he is trunked to core02 - that is not layer 3 - the trunk should have nothing to do with him using the layer 3 on core02.

Please help - I dont want him using the secondary vrrp.

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  • 1
    What is the gateway address configured on the host? – Ron Trunk Aug 25 '17 at 15:00
  • Are these two Nexus configured for vPC? – John K. Aug 25 '17 at 16:25
  • Yes it is a VPC and the gateway is the VRRP 1 IP 172.19.1.1 – Alex Tomko Aug 25 '17 at 16:33
  • It starts with an arp. Does the arp show the Mac of 17.1.1? Could the arp entry be static or need flushed? – Fixitrod Aug 25 '17 at 17:49
  • Did any answer help you? If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you can provide and accept your own answer. – Ron Maupin♦ Feb 19 '18 at 18:10
2

In the case of vPC configurations, both HSRP/VRRP peers will actively route packets when they receive them. It is a special behavior for vPC.

Some information on vPC active/active routing

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