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Cisco Bug: CSCuq79793 - IPv6 ND processes NA with Link-layer address 0000.0000.0000 as valid

Last Modified

Sep 10, 2019

Products (8)

  • Cisco Nexus 7000 Series Switches
  • Cisco Nexus 7000 10-Slot Switch
  • Cisco Nexus 7000 4-Slot Switch
  • Cisco Nexus 7700 6-Slot Switch
  • Cisco Nexus 7700 18-Slot Switch
  • Cisco Nexus 7000 18-Slot Switch
  • Cisco Nexus 7000 9-Slot Switch
  • Cisco Nexus 7700 10-Slot Switch

Known Affected Releases

6.2(8a)

Description (partial)

Symptom:
IPv6 ND will install a neighbor entry for an IPv6 host that sends a NA who's Link-layer address field is populated with mac address 0000.0000.0000:
 
N7K# show debug logfile arp
2010 May 15 01:07:49.931933 icmpv6: Received NA from 2405:200:311:51::11 on Vlan666(Ethernet8/3)(Ethernet8/3) to 2405:200:311:51::1, length: 32, hop_limit: 254, ismct: 0, peergwayrx: 0
2010 May 15 01:07:49.932089 icmpv6: NA has flags: RSO
2010 May 15 01:07:49.932103 icmpv6: "Target Link-layer Address" TLV present
2010 May 15 01:07:49.932118 icmpv6: icmpv6_nd_check_adjacency: nd_adj 0x9107f94 got from ICMPv6 iftype for neighbor 2405:200:311:51::11 (0 3 1) on interface Vlan666
2010 May 15 01:07:49.932130 icmpv6: icmpv6_nd_get_adjacency: (0x9107f94) Found adjacency 2405:200:311:51::11 (0 3 1) in SDB on interface Vlan666
2010 May 15 01:07:49.932168 icmpv6: icmpv6_nd_add_adjacency: (0x9107f94) adj_mac: 0000.0000.0000, mac in packet: 0000.0000.0000, stale_request: 0
2010 May 15 01:07:49.932190 icmpv6: icmpv6_nd_start_reachable_timer: (0x9107f94) Set expires timer to 22 sec for a neighbor 2405:200:311:51::11 (0 0 0) on Vlan666
2010 May 15 01:07:49.932209 icmpv6: icmpv6_nd_set_reachable_state: (0x9107f94) Entering REACHABLE state from INCOMPLETE for 2405:200:311:51::11 (0 0 0) on interface Vlan666
2010 May 15 01:07:49.932254 icmpv6: icmpv6_nd_add_adjacency: (0x9107f94) Update timestamp for neighbor 2405:200:311:51::11 (0000.0000.0000) (0 0 0) learnt on interface Vlan666 in SDB. local_ptr: 0x9107f94
2010 May 15 01:07:49.932283 icmpv6: -----
2010 May 15 01:08:11.944708 icmpv6: icmpv6_nd_ager (0x9107f94) Current State REACHABLE
2010 May 15 01:08:11.944850 icmpv6: icmpv6_nd_set_stale_state: (0x9107f94) Entering STALE state from REACHABLE for 2405:200:311:51::11 (0 0 0) on interface Vlan666
2010 May 15 01:08:11.944864 icmpv6: icmpv6_nd_set_stale_state: (0x9107f94) Set expires timer to 1476 sec for a neighbor 2405:200:311:51::11 (0 0 0) on Vlan666
 
F340.14.06-7700-1# sh ipv6 neighbor
 
Flags: # - Adjacencies Throttled for Glean
       G - Adjacencies of vPC peer with G/W bit
 
IPv6 Adjacency Table for VRF default
Total number of entries: 1
Address         Age       MAC Address     Pref Source     Interface
2405:200:311:51::11
                00:04:13  0000.0000.0000  255  icmpv6     Vlan666

Conditions:
Nexus 7000 or 5000 receives an IPv6 Neighbor Advertisement from a host with the following MAC address populating the Link-layer address field:
 
0000.0000.0000
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