Test VMkernel network connectivity with the vmkping command

Connect to the ESXi host using an SSH session and run this command:

vmkping -I vmkX x.x.x.x

Where x.x.x.x is the hostname or IP address of the server that you want to ping and vmkX is the vmkernel interface to ping out of.

If you have Jumbo Frames configured in your environment, run the vmkping command with the -s and -d options.

vmkping -d -s 8972 x.x.x.x

Note: In the command, the -d option sets DF (Don't Fragment) bit on the IPv4 packet. 8972 is the size needed for 9000 MTU in ESXi.
To test 1500 MTU, run the command:

vmkping -I vmkX x.x.x.x -d -s 1472

Verification of your MTU size can be obtained from a SSH session by running this command:

esxcfg-nics -l

Output should be similar to:

esxcfg-nics -lName PCI Driver Link Speed Duplex MAC Address MTU Description

vmnic0 0000:02:00.00 e1000 Up 1000Mbps Full xx:xx:xx:xx:xx:xx 9000 Intel Corporation 82545EM Gigabit Ethernet Controller (Copper)
vmnic1 0000:02:01.00 e1000 Up 1000Mbps Full xx:xx:xx:xx:xx:xx 9000 Intel Corporation 82545EM Gigabit Ethernet Controller (Copper)

esxcfg-vmknic -l

Output should be similar to:

esxcfg-vmknic -l

Interface Port Group/DVPort IP Family IP Address Netmask Broadcast MAC Address MTU TSO MSS Enabled Type

vmk1 iSCSI IPv4 10.10.10.10 255.255.255.0 10.10.10.255 XX:XX:XX:XX:XX:XX 9000 65535 true STATIC