Hello,
The problem with this OID is that if you are not using the default vlan you need to map it to any active vlan if you are using v2 you can do the following :
snmpwalk -v2c -c <public@vlan#> <ip add> ipNetToMediaPhysAddress.
For version 3 you need to configure a context and map that context to the SNMP group, then in the context you need to add the context name to the walk as below:
snmpwalk -v3 -l authPriv -u snmp-poller -a SHA -A "PASSWORD1" -x AES -X "PASSWORD1" -n <context name> <ip add>
check first with version two and any active vlan and you will see the information being displayed.
Regards,
Claudio G