Duplicate MACS

When I run the duplicate MAC report from CM the report shows over 2,500 duplicate MAC addresses on our network.
I'm sure this isn't correct as the MACs that are showing as duplicates show twice on the same port (once on the voice vlan and once on the native vlan)
Is this a bug? Is there a way to fix this? I've attached an example from the report.

Hi Joe,
I've looked into this a bit further today and can now confirm that 99% of the reported duplicates are infact IP Phones. There are a few of PC's and Servers reported as duplicates but these can be explained (ie, clustered servers, etc). I'm still not sure why the IP Phones are being reported as duplicated though?
When I do a "show mac address table int fa0/xx" on a switch I get the output below.
Vlan    Mac Address       Type           Ports
109    000b.fd5d.f173    DYNAMIC     Fa0/14
217    000b.fd5d.f173    DYNAMIC     Fa0/14
000b.fd5d.f173 is an IP Phone
VLAN 109 is the data VLAN
VLAN 217 is the Voice VLAN
Is there away that I can prevent these appearing as duplicates so the report can be more accurate?

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Duplicate MAC Addresses effect

Hi All,
I have a query regarding the entry of duplicate MAC entries in switch. I tried issuing the following command:-
Switch(config)#mac address-table static 0007.e9f6.4fd2 vlan 1 interface fa0/2
Switch(config)#mac address-table static 0007.e9f6.4fd2 vlan 1 interface fa0/3
And after issuing the command, the resultant MAC table was as follows:-
1 0007.e9f6.4fd1 STATIC Fa0/2 Fa0/3
What does this signify. Where would a packet destined to this MAC address reach (I mean the port that it will reach)
Does it mean that there could be Network Load Balancing?
Thanks,
Sridhar.

HI
It will reach to the port where the end system is connected.u just deifined the mac-address as static on two ports u will not connect the end system to two ports so on the port which u r end system will connected will be up/up and on the port which the end system is not connected it will be in down state.hope i am correct in this if not plz correct me.
Thanks
Mahmood

LMS4.1 aggregated duplicate MAC-Report

Hello,
We want to quickly identify ports with probably attached mini-switches/hubs. Does a report type exist in LMS4.1 showing duplicate MACs aggregated with its count of occourence, not line by line?
Is it planed to bring out basic aggragate functions (avg,min,max,sum,count) into LMS/PI Report-Generator to be able for a real flexible reporting without the need for accessing database directly?
Steffen

I can't disagree with your logic, I guess I just assumed such an enterprise solution (that is FAR from cheap) wouldn't require an export of my close to 20,000 records to a .csv in order to do simple sorting.
I will continue to look for a solution within the application, but if worse comes to worse i guess an export could suffice for some of what i'm trying to do.

WGM - Can't add computers due to duplicate MAC address

Hello all,
I'm having a problem with 10.5.4 Server where once a computer is deleted from WGM it can't be added back. WGM gives an error message about duplicate MAC addresses. It appears that, although the deleted computer is no longer listed, the MAC address and name seem to still either be cached or in the database.
Any ideas?
Thanks

Saw you have no replies yet... did you ever get this issue figured out?
It's a shot in the dark, but years back we used to get zombie Macs (er, MACs) that would not show up in the list of computers, but were "still in the system" as a damaged record. Try enabling the "All Records" tab from the WGM prefs and searching for the computer record there, within the "Computers" list. If you can find them, deleting them should allow you to add them back in normally.
Let us know. Cheers, Joel

Duplicate MAC Addresses?

Hi Folks,
Has anyone experienced duplicate MAC addresss issues with the UCS-B/6120 connected to a 6500? I'm seeing the following on my 6500:
6506#sh arp | inc 0025
Internet 10.1.79.60             0   0025.b501.0005 ARPA   Vlan210
Internet 10.1.79.62             4   0025.b501.0007 ARPA   Vlan210
Internet 10.1.79.98            51   0025.b501.0005 ARPA   Vlan210
I checked my profiles and they appear to each have a uniquely assigned MAC address.   The correct entry is 10.1.79.60 and the 6120 should be replying with 0025.b501.006 for 10.1.79.98.
Anyone got any thoughts on how to correct this issue?
Take Care
Jason

There is nothing wrong with what you're seeing. It's acceptable to have N IP addresses resolve to 1 MAC
address. That is the case with secondary IP addresses for instance, Proxy-ARPing, "plumb" interfaces, etc.

Duplicate Mac contacts in Skype

In my Skype contacts, all the contacts from my Mac address book (which is a sync with my Gmail account) are duplicated. If I untick the "show mac contacts" option in Skype, they all disappear as expected, but re-ticking that box brings them all back twice. I've searched around and seen a few others with the same problem, but no explanation or solution yet. Any thoughts? Anyone else experience this?

This is how contacts work at the moment. If you tick the box to see your Mac Contacts, they show up in the contact list, but they don't merge with your Skype or Facebook contacts. There are different contact groups, which you can see above the contact list itself. "Skype" will give you only Skype contacts, whereas "Address Book" will give you only AB contacts. But if you're looking at the "All" list, then yes, you will see duplicates.
More info is available here: https://support.skype.com/en/faq/FA10899/can-i-call-my-address-book-contacts-in-skype-for-mac-os-x

Duplicate MAC addresses on touch panels

I have 2 TPC 2012 touch panels (out of 15) with the same MAC address. Of course since the MAC address is the same, this causes network problems such as duplicate DHCP assigned IP addresses.
How can this happen?
How do I fix it?
Message Edited by dbtestcon on 09-18-2008 02:46 PM

Hello,
Before we go any further, I need to confirm that the MAC addresses are really the same. I need you to submit a screenshot of the two addresses.
Can you type ipconfig/all in your command prompt. Take a screen shot of the Physical Address. Also, go to control panel > network connections > local area connection. Right-click and go to Properties. Left-click on Configure. Take a screenshot of the Advanced Tab as well. Post those and we'll go from there.
National Instruments
Applications Engineer

Duplicate Mac in iCloud

I need help with something. It is not urgent, but it is frustrating me.
I recently wiped and restored (from a Time Machine backup) my MacBook Pro with Retina Display. After doing so, I set it up again and signed in to iCloud. Same device, no other Macs, but for some reason it is now showing that there are two MacBooks in Find My Mac and in other places. For example, when removing a Mail account from System Preferences under Internet Accounts, it says, "Removing from all computers using iCloud Keychain will remove it from this Mac and 'X’s MacBook Pro'". I don't understand this, because "this Mac" and "X's MacBook Pro" are the same device. Is there a way to remove this duplicate device from iCloud?

Hello cargeekschmid,
Because your Mac was not removed from your iCloud account before you erased, it technically thinks that you have started a new device. What you can do to remove it is to go to icloud.com/#find and sign in. Look at the devices available and remove the one that it does not find.
iCloud: Remove your device from Find My iPhone
http://support.apple.com/kb/ph2702
Regards,
-Norm G.

Duplicate Mac Mail notes

Whenever I sync my BB with my notes in Mail.app on my Mac, I end up with multiple copies of notes on the Blackberry. There's only one copy of each note in mail.app, but even if I reset iSync history, reboot the Mac, wipe all the notes from the Blackberry and then select the "Replace all notes on this Blackberry device" option in Blackberry Desktop Manager, I still end up with multiple copies. What is going on? Has anyone else seen this behaviour?
If I then edit one of the notes on my Blackberry, then run a two-way sync, I end up with 3 copies of the note, of which 2 are original and one the edited version, and 2 copies on the Mac.
I'm running:
Bold 9700 v5.0.0.321
Blackberry Desktop Manager 1.0.2 (build 8)
Mac OS X 10.6.2 (Snow Leopard)
However, I had this problem previously when I was running Leopard and a Bold 9000.
Any ideas on how to fix it?

I've recently come across a couple of good threads which have info on this problem:
1. There seem to be some issues between Mac Mail and IMAP access to Gmail which cause notes to be saved in different places (under different labels in Gmail):
http://forums.macrumors.com/showthread.php?t=407306
2. Making sure Notes are only created "On My Mac" can help:
http://discussions.apple.com/thread.jspa?threadID=1376224
However, even after following all this advice (and doing other stuff like wiping the databases on my Blackberry), I still get 5 copies of each Note on my Blackberry, when there's only 1 in the Notes. So I thought I'd try a spotlight search for some of the text in one of my notes, which happened to be "Corelli Mandolin". Hey presto, 5 copies of the "Mail Message" (e.g. Note) turn up in different archive folders in Mail. See attached screenshot.
After deleting the 4 other copies of mail (except the one in ~/Library/Mail/Mailboxes/Notes.mbox which is the real one), the problem is fixed for me.

Thinkcentre Edge M-Series with duplicate mac address

We have a lot of Edge M-Series all with the same MAC address appears in Bios (F1), using Windows 8.1 perhaps need to modify media access control with custome address, it's there an Bios update available or any issue to fix this ?

Have you updated to the latest BIOS?
If so, then: In device manager/network adapters, check the intel ethernet device, under the advanced tab, the ability to set the locally admin address (MAC.)

Duplicate MAC Address on HP 8530p

Hi all
We just have figured out, that we have more then one HP Elitebook 8530p with the same MAC address. Special is, that the MAC address is in a unusual range. It has the number 88:88:88:88:87:88. There are more then one notebook that has the same MAC. We have updated the BIOS to the latest available, but without a solution. Also in the BIOS there is no way to change it physical.
We need a unique MAC because we do deploy the OS with PXE in SCCM and therfore it must be unique.
Any hint what we can do in this manner?
Kind regards, Stefan

Print a Wireless Network Test.
I hope you are not using this for MAC filtering on your router. It is pretty much a useless security method.
Read more here.
Say thanks by clicking "Kudos" "thumbs up" in the post that helped you.
I am employed by HP

ISG session with duplicate mac addresses - ASR 1k

Hello all,
I have an issue with current ISG implementation on ASR 1k.
We have subset of subscribers that are authenticated based on their mac address and another subset that are authenticated based on their c-vlan/s-vlan tag which is derived from nas-port-id. If two subscribers have identical mac addresses and one is authed based on mac and the other is based on c-vlan/s-vlan, the last one to auth kicks the previous authenticated session and takes it's place, which is totaly unacceptable.
For subscribers with mac based auth, session initiatior is unclassified mac address, as for c-vlan/s-vlan based auth it is dhcp request.
Forgive the lack of details, if anything I am ready to supply any available and open info. Personaly I think this is just shortcoming of ASR 1k s ISG implementation, because I know for a fact that 9K BNG handles this situation very well and has a more precise definition of c-vlan/s-vlan than 1k.
Any ideas on how to tackle this?

Hi,
Not sure if it would be possible since mac address is probably being used as a session key for both sessions (that's why the latest subscriber to come up, takes over the first one) even if you are using different identifiers (mac-address vs c-vlan/s-vlan).
Are these L2 subscribers or routed subscribers?
Could you provide a configuration of the ISG?
Regards.

'Show Mac Contacts' creates duplicates

NOT SOLVED AS OF - July 10, 2015 Does ANYONE know how to solve this issue: Checking the 'Show Mac Contacts' in Skype Preferences creates duplicates of all my address book contacts. I've searched the forums and there is a moderator who has offered a 'solution' to this on a similiar threads:http://community.skype.com/t5/Mac/Duplicate-Mac-contacts-in-Skype/td-p/2034871However many people, including myself, have responded that the problem has not been solved. Yet any similiar questions have been archived and this answer given as a solution. Anyone have a sloution?? Thanks for taking the time to read, and possibly offer a solution to all the users who are encountering this problem. :

I am using Outlook 2007 on my PC.
I am not using Mobile Me; rather I am running the sync on my PC using iTunes. The duplicates were on both my iPhone and my computer, but they didn't always appear to be identical. It is somewhat complicated by the fact that I use Plaxo to update my contacts folder(s) on my PC.
I worked with Plaxo to combine all contacts folders, and then I went through each item and deleted all duplicates. Then I synced with my phone, and finally got it down to one unduplicated list. This was tedious, since I have over 1,000 contacts.
Now I am getting ready to sync, and I am not sure what to check on the sync menu. It asks whether I want contacts added on the phone synced to my Collected Contacts folder. Why add it to a separate folder instead of my main contacts folder? Does this add a separate item that you then use to update the main folder?
Thank you and sorry for all the questions.

HSRP - Duplicate address on Vlan, sourced by mac-address

Hi ,
Network structure
Switch A --- Customer firewall 1
|
Switch B --- Customer firewall2
May be some one can help me.
There was a nagious alert yesterday and on investigation I found the 'Duplicate address x.x.x.x(VIP) on Vlanxxx, sourced by 0006.b19c.c5d9' error
It a HA feed from our switches which is going to customer firewalls.
On further investigation I have found on our switch A the ARP table is not learning the VIP address from this mac-address where as on switch B is learning the VIP address through mac 0006.b10c.c8d9 which is customer sonic firewall which is not a normal behaviour.
Our switches are Cisco 3560 switch.
Please if you could let me know what causing this.

Hi mcgowan,
Yes, there is duplicate MAC. But, its duplicate between interface vlan address and virtual MAC address on HSRP.
when I type command :
show mac address | i 0000.0c07.ac01
It shows me :
100 0000.0c07.ac01 STATIC CPU
I think this MAC generate by system on HSRP. Currently I shutdown interface vlan 100 on switch A, like as your suggestion. But the impact is my client will get trouble when switch B is down, because HSRP is not running well.
Regards,
Rakhmad

How to remove duplicate songs from Itunes

I've consolidates my music in Itunes 11.01. Playlists are just getting crazy with duplicates.
I want to eliminate duplicate music files, as well as eliminate the references in the interface.
Then sync my new IPad.
When I manually erase a duplicate in Windows Explorer, I'm left with a "!" indication in Itunes that the file cannot be found... duh.
I want to find either an easier way to eliminate duplicates without Windows Explorer, or
a way to select all the "!" references in Itunes interface and delete.
Help please from a completely organized person who hates Apples "intelligence" at thinking it knows what I want, and not providing
adequate help under "remove duplicates" in its help index.
Thanks.

How to find and remove duplicate items in your iTunes library - http://support.apple.com/kb/HT2905
Posts by turingtest2 about different types of duplicates and techniques - https://discussions.apple.com/thread/3555601 and https://discussions.apple.com/message/16042406 (Note: The DeDuper script is for Windows).
May 2014 post on iCloud duplicates - https://discussions.apple.com/message/25867873
Show exact duplicates (Mac and Windows) - https://discussions.apple.com/message/16951281
http://dougscripts.com/itunes/itinfo/dupin.php (commercial)
iTunes Duplicate Song Manager - http://sourceforge.net/projects/itunesdsm/
http://www.hardcoded.net/dupeguru_me/
http://www.wideanglesoftware.com/tunesweeper/index.php
http://www.araxis.com/find-duplicate-files (commercial, free trial) - finds duplicate files on computer, not specifically iTunes
I would do it manually. As you can see from turingtest2's post, some duplicates are not really duplicates.
I would also review how you add media to iTunes. It should not be producing all that many duplicates.

Duplicate MACS

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