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Cisco Bug: CSCur39024 - Unable to remove multiple ipv6 nd prefixes configs from interface

Last Modified

Sep 11, 2019

Products (6)

  • Cisco Nexus 3000 Series Switches
  • Cisco Nexus 3064 Switch
  • Cisco Nexus 3016 Switch
  • Cisco Nexus 3064-T Switch
  • Cisco Nexus 3048 Switch
  • Cisco Nexus 3132Q Switch

Known Affected Releases


Description (partial)

"Unknown Prefix/Can not be deleted" error is seen when removing second prefix with the same length under interface.

N3k(config-if)# no ipv6 nd prefix 2001:100:e102:10a0::/64 infinite infinite no-autoconfig
Unknown Prefix/Can not be deleted

Interface's configured with multiple IPv6 ND prefixes covering the same range configured under interface and the range isn't a configured prefix you may run into a condition where you are unable to remove the configuration.

Example config:
interface Vlan20
  ipv6 address 2003:1000:705:3c::2/64
  ipv6 nd prefix 2003:1000:705:3c::/64 infinite infinite no-autoconfig
  ipv6 nd prefix 2003:1000:705:3c::2/64 infinite infinite no-autoconfig
  ipv6 nd prefix 2001:100:e102:10a0::/64 infinite infinite no-autoconfig  <<< please note no prefix if you remove this before the ::2 you will trigger this issue
  ipv6 nd prefix 2001:100:e102:10a0::2/64 infinite infinite no-autoconfig

If you are hitting the issue you will notice the following input in "show ipv6 nd interface (interface id) prefix"
N3K(config)# show ipv6 nd interface vlan 20 prefix 
ICMPv6 ND Interfaces for VRF "default"

  List of IPv6 Prefix advertised on Vlan20   <<< the ipv6 nd prefix configuration is present but there is no prefix for that in the prefix list.
      Prefix : 2003:1000:705:3c::/64
      Enabled : Yes
      Validlife time : infinite
      Preferred lifetime : infinite
      On-link : Yes
      Off-link : No
      Autonomous : No

Note this can also be seen if you change the ipv6 prefix on the interface before you remove the ipv6 np prefix configurations
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