1

I have two XRv routers I am running in GNS3 setup so I can ping their regular interfaces, but when I configure VRRP I can't ping the VRRP virtual IP (except from the Router currently acting as active). This issue also bleeds over to actual packet routing for the devices too (packets sent to the virtual IP as a gateway for the host used below.)

Is there a configuration option I may have missed, or is this just a known issue in the XRv software? I run into the same issue if I try using HSRP instead of VRRP.

Router Configs:

R1:

interface GigabitEthernet0/0/0/1
ipv4 address 192.168.102.101 255.255.255.0
!
!
router vrrp
 interface GigabitEthernet0/0/0/1
  address-family ipv4
   vrrp 5
    priority 150
    address 192.168.102.155
   !
  !
 !
!

R2:

interface GigabitEthernet0/0/0/1
 ipv4 address 192.168.102.105 255.255.255.0
!
router vrrp
 interface GigabitEthernet0/0/0/1
  address-family ipv4
   vrrp 5
    priority 100
    address 192.168.102.155
   !
  !
 !
!

Output from show vrrp

R1.

IPv4 Virtual Routers:
                      A indicates IP address owner
                      | P indicates configured to preempt
                      | |
Interface   vrID Prio A P State    Master addr     VRouter addr
Gi0/0/0/1      5  150   P Master   local           192.168.102.155

R2.

IPv4 Virtual Routers:
                      A indicates IP address owner
                      | P indicates configured to preempt
                      | |
Interface   vrID Prio A P State    Master addr     VRouter addr
Gi0/0/0/1      5  100   P Backup   192.168.102.101 192.168.102.155

pinging interfaces on R1 and R2 from host device (connected to both via a switch)

PC1> ping 192.168.102.101
84 bytes from 192.168.102.101 icmp_seq=1 ttl=255 time=4.854 ms

PC1> ping 192.168.102.105
84 bytes from 192.168.102.105 icmp_seq=1 ttl=255 time=5.304 ms

Pinging virtual IP from host

PC1> ping 192.168.102.155
192.168.102.155 icmp_seq=1 timeout
192.168.102.155 icmp_seq=2 timeout
192.168.102.155 icmp_seq=3 timeout
192.168.102.155 icmp_seq=4 timeout
192.168.102.155 icmp_seq=5 timeout

Pinging Virtual IP from active router (R1)

Sending 5, 100-byte ICMP Echos to 192.168.102.155, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/1 ms

Info from show arp command:

R1:

-------------------------------------------------------------------------------
0/0/CPU0
-------------------------------------------------------------------------------
Address         Age        Hardware Addr   State      Type  Interface
192.168.100.101 -          0cd1.c4b1.ed01  Interface  ARPA  GigabitEthernet0/0/0/0
192.168.100.105 00:01:32   0cd1.c4a0.ec01  Dynamic    ARPA  GigabitEthernet0/0/0/0
192.168.102.101 -          0cd1.c4b1.ed02  Interface  ARPA  GigabitEthernet0/0/0/1
192.168.102.105 00:01:32   0cd1.c4a0.ec02  Dynamic    ARPA  GigabitEthernet0/0/0/1
192.168.102.155 -          0000.5e00.0105  Interface  ARPA  GigabitEthernet0/0/0/1

R2:

-------------------------------------------------------------------------------
0/0/CPU0
-------------------------------------------------------------------------------
Address         Age        Hardware Addr   State      Type  Interface
192.168.100.105 -          0cd1.c4a0.ec01  Interface  ARPA  GigabitEthernet0/0/0/0
192.168.102.105 -          0cd1.c4a0.ec02  Interface  ARPA  GigabitEthernet0/0/0/1
192.168.102.155 -          0000.5e00.0105  Standby    ARPA  GigabitEthernet0/0/0/1
5
  • I'd blame GNS3. Check that PC1 is getting an ARP answer for the VIP.
    – Ricky
    Sep 20, 2021 at 21:53
  • I am seeing arp responses when I monitor the network with Wireshark. I can see the Ping messages reaching the link the active router is on, there just aren't any replies to it.
    – Colin Z
    Sep 20, 2021 at 22:03
  • Do you see an ARP entry on both R1 and R2 for the floating IP, specifically where both routers have the ARP listed as "self"?
    – ditrapanij
    Sep 21, 2021 at 12:29
  • I have added the output from show arp to the post. The active router shows the floating IP arp as a local interface, and the standby lists it as standby.
    – Colin Z
    Sep 22, 2021 at 13:59
  • @ColinZ, I have this exact same issue on a pair of NCS55A1s where I cannot hit the floating IP from very specific locations with ICMP. I've got a TAC case open where they have advised this is expected behaviour. Continuing to work through this with them to confirm that is the case.
    – ditrapanij
    Sep 23, 2021 at 12:08

2 Answers 2

1

Virtual Mac still does not work but you can force it to use bia with hsrp use-bia

RP/0/0/CPU0:R1#show version
Fri Aug 11 15:05:18.707 UTC

Cisco IOS XR Software, Version 6.1.2[Default]
Copyright (c) 2016 by Cisco Systems, Inc.

ROM: GRUB, Version 1.99(0), DEV RELEASE


RP/0/0/CPU0:R1#show run router hsrp
Fri Aug 11 15:04:33.690 UTC
router hsrp
 interface GigabitEthernet0/0/0/0
  address-family ipv4
   hsrp 123
    preempt
    address 10.0.123.254
   !
  !
  hsrp use-bia
 !
!
-1

I think it's VRRP behavior to not respond to ICMP on virtual IP per RFC

2
  • Why do you think so? Could you elaborate?
    – Zac67
    Jun 12, 2023 at 17:23
  • 1
    Agreed, I've never had a problem with ICMP and VRRP/HSRP. It seems to work as expected, the ARP reply for the virtual IP shows the MAC address of the active router and the inactive router simply does not reply for ARP/ICMP until it becomes active. Jun 12, 2023 at 18:34

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