Recently I was engaged in a discussion where for one VM, esxtop shows Dropped Packets under %DRPRX column.
In this case the VM has 4 virtual Network Interfaces configured so how to track down which interface was dropping packets. Please have a look at the esxtop output below.
Press "n" (for Networking)
Look for the VM in Question (here the name is replaced with VMName to protect the innocent :-) )
As you can see the column above, the %DRPRX column shows 5 packets dropped on the receiving interface.
Now the VM is configured with 4 different vNIC dvPortGroups so how would you find out which interface is dropping packets or which dvPortGroup is having the issue.
Note: The following command needs to be used under the supervision of VMware Technical Support only so please use it at your own risk in non-Production Environment.
Now use the following command and note down the information
/usr/lib/vmware/bin/net-dvs | lesscom.vmware.common.port.connectid = 207541228
com.vmware.common.port.portgroupid = dvportgroup-54112com.vmware.etherswitch.port.vlan = 44
com.vmware.common.port.volatile.status = inUse linkUp blocked portID=220334
The above command was used on a particular version of ESXi so the path to net-dvs may vary depending on the version in use.
So its using dvportgroup-54112 and VLAN 44.
Now use the same command again and drill down to dvportgroup 54112 and look for the pgmap section:
/usr/lib/vmware/bin/net-dvs | less
dvportgroup-54112 <-> ->dvPortGroup4
Now as you can see here the particular dvporgroup ID is mapped to dvPortgroup4 so now you can go back to vSphere Client and check the settings on the VM and see which vNIC is tied up with dvPortGroup4 or you can go to Inventory - Networking and under the VDS you can see the names of the dvPortGroup/s and find out the VM by clicking on that particular dvpg and on the right pane click on the Virtual Machines Tab.
Another way to confirm the same is by using the MOB (Managed Object Browser)
Hopefully this will make your life easy !!
Please share !!