OSPF Neighbor error with VRRP ?

[phamsyhung2110]

Hi everyone,

I have 2 routers Mikrotik and Cisco running VRRP and OSPF together.

My Mikrotik router has very many logs as:
-Discarding packet: destination address is not a multicast or local address
-OSPFv2 neighbor 172.16.9.3: state change from ExStart to 2-Way
-OSPFv2 neighbor 172.16.9.3: state change from ExStart to Init
In the Neighbor Tab, I see very much count of state change (about >4000 times)
This router has 2 neighbors and the switch core neighbor is stable, but the router Cisco Router neighbor with router-id 172.16.9.3 is had a problem like above.
Three routers have advertised the same network is 172.16.9.0 and the router-id is unique.

In another branch of my company, I also have 2 routers Mikrotik running OSPF together but not running VRRP so they are very stable.

Is the problem is from VRRP ?

Thanks!

[Georg Pauwen]

Hello,

as far as I recall, Cisco uses VRRPv2 by default, whereas Mikrotik uses VRRPv3 by default. Make sure the versions match on both sides.

Also, is the Mikrotik using a /32 address as the VRRP IP (as in the example below) ?

/ip address add address=192.168.1.1/32 interface=vrrp1

[phamsyhungba]

I use /24 network for VRRP and as same as the main network:

main network: 192.168.1.0/24

vrrp: 192.168.1.1

Mikrotik: 192.168.1.2

cisco: 192.168.1.3

both are vrrp ver 2

[Georg Pauwen]

Hello,

so what VRRP address do you have configured on the Mikrotik ?

/ip address add address=192.168.1.1/32 interface=vrrp1

or

/ip address add address=192.168.1.1/24 interface=vrrp1

You also might want to try and set VRRP version 3 on both devices.

[phamsyhungba]

I configured /24 on both routers, the VRRP is working for a long time,and  my main problem is the OSPF error state 

[Georg Pauwen]

Hello,

what happens when you set the VRRP on the Mikrotik to a /32 ?

/ip address add address=192.168.1.1/32 interface=vrrp1

?

[phamsyhungba]

I haven't tried yet, but Can VRRP  work with a different network of IP address with 2 routers?

I meant Can vrrp work with subnet /32 while the LAN network of 2 routers is /24?

[Georg Pauwen · Accepted solution]

Hello,

the Mikrotik manual specifies that setting as recommendation:

--> address on VRRP interface must have /32 netmask if address configured on VRRP is from the same subnet as on router's any other interface.

[phamsyhung2110]

Can you explain it? I don't understand

Why did the subnet of VRRP IP must be /32?, and How does it relevant to the OSPF neighbor error?

Thanks very much!

[phamsyhung2110]

And when I change IP of vrrp to /32 subnet, because I'm using the default route from switch core to vrrp, so do I must change the next-hop of this default route ? Or must I advertise this /32 network to OSPF and all network systems?

[Georg Pauwen · Accepted solution]

Hello,

it looks like Mikrotik wants OSPF to see the virtual IP address as a separate interface. Apparently that is Mikrotik-specifc, because on a Cisco device, there is no such requirement.

What default routes are you using (the OSPF generated ones) ?

[phamsyhung2110]

I use the default route from the switch core to the IP of VRRP

The switchcore is work as a router and also running ospf with the same network 192.168.1.0/24 and same area.

For an example:

Mikrotik:192.168.1.2/24

Cisco router: 192.168.1.3/24

VRRP: 192.1681.1/24

On cisco switch core I use: IP route 0.0.0.0 0.0.0.0 192.168.1.1

Back to the OSPF problem, on the Mikrotik router I see very many logs:

  Discarding packet: destination address is not a multicast or local address

   expected=192.168.1.2 (The IP of Mikrotik)

    got=192.168.1.1 (The IP of VRRP)

     source=192.168.1.3 (The IP of cisco router)

And in the Neighbor Tab on Mikrotik,I see 2 neighbor overlaps:

    neighbor 192.168.1.3 interface: LAN (port with IP 192.168.1.3)

    neighbor 192.168.1.3 interface: vrrp