Trouble shooting network issue ,Part1, introduce some command

ESXi offer some command and tools to trouble shooting network issue, I just share my experience .

Monitor the network static 

Check vswitch port statics 

Actually , you can check vswitch port statics like a physical switch 

physical switch port check，

We can get similar result from esxi vswich port . 

First, run "net-stats -l" get the portID of VM, client name 
Second,run "esxcli network port stats get -p portID"

Check the physical NIC stats

esxcli network nic stats get -n vmnicX

This command will show more details from NIC driver

ethtool --statistcs vmnicX

Capture packet tools

There are two tools for capturing packet on ESXi, tcpdump-uw and pktcap-uw

Please keep in your mind.tcpdump-uw only can capture the vmkernel traffic. When you want to trouble shooting vmotion ,vsan , HA related network issue. tcpdump-uw is very helpful.

But , if you want to trouble shooting some vm traffic issue, pktcap-uw is your best option.

So after esxi 5.5, a new tool pktcap-uw ,I will discuss this command at my next blog.