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Perttu
Enthusiast
Enthusiast

How do I print ARP table for vMotion network

Hi all,

Command esxcli network ip neighbor list shows only an ARP table of a default netstack. Is there a way to print the ARP table for vMotion netstack instead? Just found out that two hosts share a same IP (accidentally by a human error) for vMotion vmkernel interface and I'm now curious to know which one was picked by the ARP?

BR, Perttu

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Perttu
Enthusiast
Enthusiast

A follow-up. I also noticed that first (fastest) ARP response seems to be picked up by the netstack and others just ignored. If we look the following picture with two ARP responses, the first from 62:16:c3 won the race.

Screenshot 2020-12-04 at 16.29.17.png

An another thing, I wanted to know how ESXi notifies the admin from a duplicate IP address. And the answer is that only with a single line in the vmkernel.log.

2020-12-04T11:57:54.555Z cpu38:2099384)Tcpip_Vmk: 124: arp: 00:50:56:68:ef:91 is using my IP address 172.16.101.32 on vmk1!
2020-12-04T12:17:32.287Z cpu47:2099384)Tcpip_Vmk: 124: arp: 00:50:56:68:ef:91 is using my IP address 172.16.101.32 on vmk1!

That's all? No events, no alerts, nothing in GUI. I suppose this fairly common error to appear as people do type these addresses as static and hence by hand. 

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