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On a production Nexus 5K, I noticed the following piece of config: 

interface Vlan1
  mac-address 0000.0000.0000

This is the entire Vlan1 stanza. What does this accomplish?

belacqua
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    Are you the only technician that has access to this switch? I'm wondering if someone manually put this in there. If that is a possibility, I may be able to give you additional insight. – Ryan Foley Mar 07 '14 at 08:09
  • @Fizzle That is the case -- there are other people with access, and I suspect this was manually put in to address ... something. Initially I discovered this as I was auditing configs and sync between 5Ks. – belacqua Mar 07 '14 at 22:25
  • Is there a Cisco ACE on the subnet? How about a Layer 3 card? We ran into an issue on a Nexus 7k where there was strange interaction between vPC, ACE and pinging SVIs that required statically setting the SVI MAC Address – Ben Mason Mar 31 '14 at 12:58
  • No ACE on the subnet, so unfortunately can't be that bug. Thanks. – belacqua Mar 31 '14 at 23:12
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    It could be an attempt to disable vlan 1 by someone who mistakenly thought that was a good thing to do on a cisco switch. – Todd Wilcox Mar 19 '15 at 02:21
  • It could be a rubbish "security through obscurity" technique, trying to force the SVI to have a MAC address of all zeros which is invalid so no one can communicate with the VLAN 1 instance. I'm not well exerpainced with Nexus switches, do they have a vlan 1 interface that can't be deleted like traditional IOS switches? – jwbensley Apr 27 '15 at 11:30
  • Did any answer help you? if so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you could provide and accept your own answer. – Ron Maupin Aug 10 '17 at 03:20
  • @RonMaupin Sadly,no – belacqua Aug 10 '17 at 17:18

1 Answers1

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Might be related to this known bug?

https://tools.cisco.com/quickview/bug/CSCua02927

GeorgeB
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