Today we had duplicate ip issues between two SVIs with the same ip address ; one SVI was admin down...?
We saw some traffic on the down/down SVI :
#sh int vlan402
Vlan402 is administratively down, line protocol is down , Autostate Enabled
Hardware is Ethernet SVI, address is 4cbc.48a5.827b (bia 4cbc.48a5.827b)
Description: Vlan Mgmt
Internet address is 10.10.10.1/24
MTU 1500 bytes, BW 1000000 Kbit/sec, DLY 10 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive not supported
ARP type: ARPA, ARP Timeout 04:00:00
Last input 1d10h, output 2d04h, output hang never
Last clearing of "show interface" counters never
Input queue: 0/375/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 9000 bits/sec, 13 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
146435 packets input, 10955861 bytes, 0 no buffer
Received 0 broadcasts (0 IP multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
555 packets output, 33300 bytes, 0 underruns
0 output errors, 2 interface resets
0 unknown protocol drops
0 output buffer failures, 0 output buffers swapped out
How is that possible ?
thanks in advance.
Not so sure i understand, Duplicate ip addressing is being reported . so what is the question?
Thanks for your quick reply.
My question is, how is it possible to have a duplicate ip sourced by an inactive SVI (admin down), and traffic raising on that SVI ?
If the interface is in a admin down state then it possible to manually duplicate an interface address with another and the software will let you do it, The switch/router should complain about it however i think the duplicate addressing will still take.
So that's a possibility for the duplicate, as for the interface stats i see the interface counter haven't been cleared so it is possible your seeing a ghost entry?
Another possible reason it could be a bug has @Georg Pauwen mentioned?