MX VRRP MAC Address bug ?

[RaphaelL]

Hi ,

We have multiple warm spaces and I have been taking packet capures and this is what I found : 

MX450 Warm Space 15.40 VRRP MAC ADDRESS : e0:cb:bc:a3:9b:f8 burned-in MAC : e0:cb:bc:a3:9b:f8 ( Passthrough )
MX450 Warm Space 15.42.1 VRRP MAC ADDRESS : 2c:3f:0b:e6:ba:47 burned-in MAC : 2c:3f:0b:e6:ba:47 ( Passthrough )
MX250 Warm Space 14.53 VRRP MAC ADDRESS : cc:03:d9:25:be:f9 burned-in MAC : f8:9e:28:25:be:f9 ( Routed )

Does anyone have a Warm space with 15.44 or 15.44.1 that is willing to do a packet capture and compare with my finding ? It MIGHT be fixed in 15.44 or 15.44.1 but I'm not too sure.

Also , the MS documentation states : "The virutal MAC address will always begin with 88-15-44" then procedes to show a screenshot with the VRRP Mac adress from the RFC 5798 ( 00-00-5E-00-01-XX   , where XX = RID ). It's a bit confusing and there is a typo ( virutal ).

https://documentation.meraki.com/MS/Layer_3_Switching/MS_Warm_Spare_(VRRP)_Overview

The MX documentation doesn't state anything about the MAC adress so you would assume it is under the VRRP standard , which is false. It would be nice to include how the MAC is selected ( The First 3 octets for the virtual mac address will be "cc:03:d9" and is based on Primary MX.

https://documentation.meraki.com/MX/Deployment_Guides/MX_Warm_Spare_-_High_Availability_Pair

Some will say that I'm picky , you are 100% right 🙂 

[Ryan_Miles]

Agreed the doc should go into more depth about how the virtual MAC process works. I will run this by MX PM for feedback.

If in the HA config you use the uplink IPs then you should see the physical MACs. If you use a VIP it will create a virtual MAC as you mentioned above.

[cmr]

I have just checked a coupe of HA pairs and have:

VPN concentrator mode - MX16.15 - virtual MAC beginning cc:03:d9, physical MACs begin e0:cb:bc (primary) and 68:3a:1e (warm spare)

Routed mode - MX16.16 - virtual MAC beginning cc:03:d9, I don't see physical MACs

[RaphaelL]

Great ! We now have answers to our questions  1- CC:03:D9 is always used on MX in Warm Space ( doesn't matter if it's concentrator or routed mode ) 2 - This ''issue'' is fixed on the MX 16.X branch , and seems to have been introduced in MX 15.XX and MIGHT be fixed in 15.44.1 ( still to be confirmed ) 

Thanks a lot for your time ! : )

[RaphaelL]

Late to the show ! But IT was fixed in MX15.44 !