Pinging devices with same IP addresses when they are connected at different times

[DavidWare52467]

Hello,

I have two devices that have the same IP address, but they are never connected to my CISCO switch at the same time. My problem is that when I first try to communicate with the device that is presently connected it fails because the two devices have the same IP address but different physical MAC addresses.

1) When I ping device #1 which is the first device I connected it is successful.

2) I then remove that device from the network and add device #2 (same IP different MAC).

3) When I ping device #2 it fails on the first two ping attempts but is successful on the second two. If I ping the device again it is successful every time and the mac address is replaced in the ARP table.

4) If I remove device #2 and add device #1 that device then fails on the first two ping attempts but is successful on the second two. If I ping the device again it is successful every time and the mac address is replaced in the ARP table.

I have two networks, one using an CISCO managed switch and another using a different brand that I believe is unmanaged.

I do not have this issue with the other brand switch. Is there something I can do to correct this issue on my CISCO switch?

Thank you!

[Jaderson Pessoa]

Well,

far as i know it is a normal behavior. It is necessary the switch learn the mac entry and after it the communication can be established. If you changed the mac address in a interface, is necessary occur the same process to learn it again.


I dont know if it will work, but map mac address statically it:

SW(config)#mac address-table static 0001.0002.0003 vlan 3 interface gigabitEthernet 1/0/8
SW(config)#mac address-table static 0001.0002.0004 vlan 3 interface gigabitEthernet 1/0/8

[ThrowingPackets86]

Exactly like said before, this is normal behavior for a few pings to be lossed initially while the device is learning the MAC address in its ARP table.

[Jaderson Pessoa]

Try the confis above and test if its work