If you are troubleshooting a network issue from an ESXi host it may be necessary for you to check the host’s arp cache. Running ‘arp’ doesn’t work on ESXi, instead use ‘esxcli network ip neighbor list’:
# esxcli network ip neighbor list
Neighbor Mac Address Vmknic Expiry State
------------ ----------------- ------ -------- -----
192.168.0.33 00:22:fb:4c:5c:d6 vmk0 1167 sec
192.168.0.71 00:0c:29:de:21:1a vmk0 1129 sec