Ethernet Switches & Routers

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Occasional Contributor
Posts: 17
Registered: ‎02-11-2013

IP: Duplicate IP addressdetected sent from MAC address interface 8/21, 142 packets

Hello all!

 

I am seeing this error in the logs.  I have vrrp-extended/ configured btw 2 devices and I am currently seeing this only on one of them:

 

IP: Duplicate IP address 1.1.1.1 detected sent from MAC address 02e0.5284.0801 interface 8/21, 142 packets

 

That mac is the mac address of the virtual mac for the vrid and 1.1.1.1 is the virtual ip configured for the vrid on the ve.

 

Device1

------------

 

int ve 2

ip vrrp-extended vrid 1
backup priority 255
non-preempt-mode
advertise backup
ip-address 1.1.1.1
enable

 

Device2

------------

 

int ve 2

ip vrrp-extended vrid 1
backup priority 255
non-preempt-mode
advertise backup
ip-address 1.1.1.1
enable

 

Port 8/21 is a tagged port to the other device.

 

Any ideas why I'm getting this message or how to fix if it's a problem?

 

 

Frequent Contributor
Posts: 144
Registered: ‎11-07-2013

Re: IP: Duplicate IP addressdetected sent from MAC address interface 8/21, 142 packets

You have more then one port connecting between the two devices right?  If so I would say the they have not formed an LACP/trunk/etherchannel.

 

Thanks

Michael. 

Thanks
Michael
Occasional Contributor
Posts: 17
Registered: ‎02-11-2013

Re: IP: Duplicate IP addressdetected sent from MAC address interface 8/21, 142 packets

On switch 1:

 

Configured trunks:

Trunk ID: 469
Hw Trunk ID: 1
Ports_Configured: 2
Primary Port Monitored: Jointly

Ports 8/21 8/22
Port Names Core: * none
Port_Status enable enable
Monitor off off
Rx Mirr Port N/A N/A
Tx Mirr Port N/A N/A
Monitor Dir N/A N/A

Operational trunks:

Trunk ID: 469
Hw Trunk ID: 1
Duplex: Full
Speed: 1G
Tag: Yes
Priority: level0
Active Ports: 2

Ports 8/21 8/22
Link_Status active active
port_state Forward Forward
LACP_Status ready ready

 

On switch 2:

 

Configured trunks:

Trunk ID: 257
Hw Trunk ID: 1
Ports_Configured: 2
Primary Port Monitored: Jointly

Ports 5/1 5/2
Port Names Core: * none
Port_Status enable enable
Monitor off off
Rx Mirr Port N/A N/A
Tx Mirr Port N/A N/A
Monitor Dir N/A N/A

Operational trunks:

Trunk ID: 257
Hw Trunk ID: 1
Duplex: Full
Speed: 1G
Tag: Yes
Priority: level0
Active Ports: 2

Ports 5/1 5/2
Link_Status active active
port_state Forward Forward
LACP_Status ready ready

 

Looks like the trunk is formed fine...unless I'm reading it wrong.

Contributor
Posts: 30
Registered: ‎12-13-2010

Re: IP: Duplicate IP addressdetected sent from MAC address interface 8/21, 142 packets

You sould not set both backup priorites to 255 (255 = max = owner). Try some other values and give your preferred device the higher one, e.g. like this:

 

device-1:

 

int ve 2

...

ip vrrp-extended vrid 1

  backup priority 250
  non-preempt-mode
  advertise backup
  ip-address 1.1.1.1

...

.

device-2:

 

int ve 2

...

ip vrrp-extended vrid 1

  backup priority 150
  non-preempt-mode
  advertise backup
  ip-address 1.1.1.1

...

.
 

 

Contributor
Posts: 23
Registered: ‎03-19-2013

Re: IP: Duplicate IP addressdetected sent from MAC address interface 8/21, 142 packets

A customer is having the same problem for their 2 VEs when doing the failover to the backup, the only difference is that in their log it apears only for 1 packet (on bothe VEs) and not 142 packets.

 

Any idea what is causing this duplicity (at least for this short period?)

 

Regards,

 

Ernesto

Brocadian
Posts: 44
Registered: ‎01-05-2012

Re: IP: Duplicate IP addressdetected sent from MAC address interface 8/21, 142 packets

It is an indication of VRRP-E state change of the backup trying to broadcast the VIP and claimed to be the master VRRP-E router.

It is suspected that your VRRP-E had flapped due to control packet missing from the congestion over the link.during that duration.& span.

You will see this message only on the master VRRP-E router, in your case, i.e. Device 1.

 

When the backup VRRP-E router, Device 2,  was not getting the expected VRRP-E hello from the master VRRP-E router, it tried to claim itself as the Master VRRP-E router and transmited the VRRP-E hellos that lead to the master VRRP-E rejecting them, 142 times,  by declaring "duplicate" VIP as detected by the master VRRP-E router.

 

Your switch 1 has higher priority, 250,  so it should be the master VRRP-E router.

Please check to confirm the VRRP-E flapping by checking the output of "sh ip vrrp-e statistics ve 2" on the standby VRRP-E router, it may be non-zero on  Transition to Master state counter ( or 142 )  and Transition to Backup state ( 1+the number on Master State ) counter.

 

This is expected behavior for the protocol when there are state changes with the Master/Standbhy VRRP-E roles, what need to resolve is why it caused  VRRP-E to flap,  most often the routers are suffering from high cpu or congested link(s) or heavry RSTP convergence.

 

Try to see what else is going on when this log msg showed up and proceed to clean up.

 

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