%IPV6_ND-4-DUPLICATE_OPTIMISTIC

[alfredobosca]

Hi folks

Last days, I am receiving again and again the next log message:

%IPV6_ND-4-DUPLICATE_OPTIMISTIC: Duplicate address FE80::5:73FF:FEA0:9 on GigabitEthernetx/x

FE80, indicates is a link-local IPv6 address so I guess it shouldn't be an issue but I would like to understand what's going on.

Could be affecting the router memory?

Best regards,

[marce1000]

 - Could be a bug , check current software version on your device; if feasible , applicable and or depending on priority you may want to try more recent software release(s) and check if the problem persists.

 M.

[Georg Pauwen]

Hello,

the only bug  could find was when an IPv6 address is configured on an SVI, which doesn't seem to be the case in your specific situation. There doesn't seem to be a workaround...

If you want to get rid of the message, either configure 'ipv6 nd dad attempts 0' on the interface that generates the log, or use a logging discriminator:

logging discriminator DAD severity drops 4 facility drops IPV6 mnemonics drops DUPLICATE_OPTIMISTIC

logging buffered discriminator DAD 100000
logging console discriminator DAD
logging monitor discriminator DAD
logging host ip_address_snmp_server discriminator DAD

[paul driver]

possible bug

[Giuseppe Larosa]

Hello @alfredobosca ,

>>

Last days, I am receiving again and again the next log message:

%IPV6_ND-4-DUPLICATE_OPTIMISTIC: Duplicate address FE80::5:73FF:FEA0:9 on GigabitEthernetx/x

FE80, indicates is a link-local IPv6 address so I guess it shouldn't be an issue but I would like to understand what's going on.

Could be affecting the router memory?

I would say no I have just made a quick search on Cisco CCO bug search with keyword " %IPV6_ND-4-DUPLICATE_OPTIMISTIC"

no matching bugs found

being the ND messages sent out as multicast this might be the sign of a bridging loop somewhere in the network or a misbehaving MLD snooping switch that adds the source port to the oilist

searching over google auto-magically finds the following:

https://bst.cloudapps.cisco.com/bugsearch/bug/CSCuf06043/?rfs=iqvred

Description

Symptom:
%IPV6_ND-4-DUPLICATE: Duplicate address

Conditions:
Configure ipv6 address on SVI interface

Workaround:
None

Customer Visible

Was the description about this Bug Helpful?

(4)

Details

Last Modified:

Feb 10,2017

Status:

Terminated

Severity:

2 Severe

Product:

(100)

Cisco 3900 Series Integrated Services Routers

Cisco AS5400XM Universal Gateway

Cisco VG204 Analog Voice Gateway

Cisco 1905 Serial Integrated Services Router

Cisco 2951 Integrated Services Router

Cisco 1812 Integrated Services Router

Cisco 888W Integrated Services Router

Cisco VG224 Analog Voice Gateway

Cisco 861W Integrated Services Router

Cisco 1803 Integrated Services Router

Cisco 881SRSTW Integrated Services Router

Cisco 878 Integrated Services Router

Cisco 892W Integrated Services Router

Cisco 886VA-CUBE Integrated Services Router

Cisco 7301 Router

Cisco 3845 NOVPN Integrated Services Router

Cisco AS5350XM Universal Gateway

Cisco 7206 Router

Cisco VG202 Analog Voice Gateway

Cisco 867 Integrated Services Router

Cisco 881SRST Integrated Services Router

Cisco 888E-CUBE Integrated Services Router

Cisco 881W Integrated Services Router

Cisco 861 Integrated Services Router

Cisco IAD888W Integrated Access Device

Cisco 887VA Integrated Services Router

Cisco 891 Integrated Services Router

Cisco 876 Integrated Services Router

Cisco 891W Integrated Services Router

Cisco 2821 Integrated Services Router

Cisco 888 Integrated Services Router

Cisco 7204 Router

Cisco 2911 Integrated Services Router

Cisco 1941 Integrated Services Router

Cisco IAD2430 Integrated Access Device

Cisco 7206VXR Router

Cisco 887VAM-W Integrated Services Router

Cisco IAD2801 Integrated Access Device

Cisco 887 Integrated Services Router

Cisco C881W Integrated Services Router

Cisco 1941W Integrated Services Router

Cisco 1801 Integrated Services Router

Cisco 887VA M Integrated Services Router

Cisco VGD 1T3 Voice Gateway

Cisco 1861 Integrated Services Router

Cisco 886 Integrated Services Router

Cisco 1921 Integrated Services Router

Cisco 3925E Integrated Services Router

Cisco 1811 Integrated Services Router

Cisco 2010 Connected Grid Router

Cisco 887VA-CUBE Integrated Services Router

Cisco IAD888 Integrated Access Device

Cisco 887VA-W Integrated Services Router

Cisco 1841 Integrated Services Router

Cisco 1906C Integrated Services Router

Cisco 886VA Integrated Services Router

Cisco 1802 Integrated Services Router

Cisco IAD887 Integrated Access Device

Cisco 888SRST Integrated Services Router

Cisco 871 Integrated Services Router

Cisco 7202 Router

Cisco 3945E Integrated Services Router

Cisco 2801 Integrated Services Router

Cisco 886W Integrated Services Router

Cisco 3825 Integrated Services Router

Cisco IAD2435 Integrated Access Device

Cisco 886VA-W Integrated Services Router

Cisco 1805 Integrated Services Router

Cisco 877 Integrated Services Router

Cisco 3825 NOVPN Integrated Services Router

Cisco 3845 RAN-O Integrated Services Router

Cisco 881 Integrated Services Router

Cisco 1861E Integrated Services Router

Cisco 2851 Integrated Services Router

Cisco 2811 Integrated Services Router

Cisco 888SRSTW Integrated Services Router

Cisco 887V Integrated Services Router

Cisco IAD2431 Series Integrated Access Device

Cisco IAD881 Integrated Access Device

Cisco 2921 Integrated Services Router

Cisco 2901 Integrated Services Router

Cisco 3845 Integrated Services Router

Cisco 3925 Integrated Services Router

Cisco 888-CUBE Integrated Services Router

Cisco IAD886 Integrated Access Device

Cisco 892F-CUBE Integrated Services Router

Cisco 7200 Series NPE-G2 Network Processing Engine

Cisco IAD887W Integrated Access Device

Cisco 7204VXR Router

Cisco 892 Integrated Services Router

Cisco 3825 IP RAN Integrated Services Router

Cisco VG224 Voice Gateway

Cisco 888E Integrated Services Router

Cisco 7201 Router

Cisco 3945 Integrated Services Router

Cisco IAD881W Integrated Access Device

Cisco 881-CUBE Integrated Services Router

Cisco 887W Integrated Services Router

Cisco 819 Integrated Services Router

Cisco IAD886W Integrated Access Device

Support Cases:

0

Known Affected Releases:

(1)

15.1(4)M

the issues is likely to appear on Cisco 3900 ISR router running 15.1.(4)M version.

the bug description does not provide any info about the impacts but the bug is classified with severity 2.

I think you should verify what router model you have using:

show version

show version | inc image

feel free to post these outputs in this thread if you need further help or you have other doubts.

Hope to help

Giuseppe