Does Gratuitous ARP erase other IP-address to MAC binding?

[jmaxwellUSAF]

Hi.

INT g0.0 = 172.16.0.1

HSRP virtual IP= 172.16.0.5.

On ROUTER1 when int G0.0 sends a gratuitous ARP to ROUTER2 stating that 172.16.0.5 lives at 0123.4567.89ab ,

...is 172.16.0.1 also, at the same time, still mapped to 0123.4567.89ab ? (Or is it permanently overwritten by the virtual IP?

Thank you.

[MHM Cisco World]

No, 
VIP of HSRP have virtual MAC address depend on version 
where 
the real interface IP have MAC of NIC (interface ).

https://www.geeksforgeeks.org/hot-standby-router-protocol-hsrp/

1. Virtual MAC address : MAC address is generated automatically by HSRP. The first 24 bits will be default CISCO address (i.e. 0000.0c). The next 16 bits are HSRP ID (i.e. 07.ac). The next 8 bits will be the group number in hexadecimal. e.g- if the group number is 10 then the last 8 bits will be 0a.
    
   Example of virtual MAC address –

   0000.0c07.ac0a

[jmaxwellUSAF]

So both ARP bindings exist in ROUTER2 cam table?

[MHM Cisco World · Accepted solution]

correct, both IP-MAC and VIP-vMAC 

[Richard Burts]

I am not sure that I 100 percent understand your question. But based on what I think I understand here is my response: I think we are talking about the arp table and not some other type of mapping or table content. If R1 would send a gratuitous arp for the HSRP virtual address it would not use the mac 0123.4567.89ab but would use the multicast mac associated with the particular HSRP group configured on the interface. So R2 would have an arp entry for 172.16.0.1 with the physical mac address and have an arp entry for 172.16.0.5 with the virtual mac address.