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Cisco Bug: CSCvs13098 - Sending unicast arp request to virtual mac address for HSRP after taking Active

Last Modified

Jul 14, 2020

Products (1)

  • Cisco MDS 9000 NX-OS and SAN-OS Software

Known Affected Releases

7.0(3)I7(6) 9.3(1)

Description (partial)

When HSRP states changes from active to standby, ARP entry learnt against HSRP vMAC in HSRP Secondary takes 30 seconds to get deleted because of arp retry logic. Due to this behaviour, arp can not be resolved thus traffic is dropped until arp entries are deleted after 30 seconds.

1. Enabled ip local-proxy-arp on HSRP Active. 
2. Have reachable host on same VLAN.
3. Ping to Host from HSRP Standby, Host will respond and HSRP active will respond because of local proxy. We will override host mac with HSRP vMAC which is the latest.
4. Now change HSRP standby state to active.
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