Not too long ago, I had to setup a set of Windows VMs on separate ESXi hosts that needed to communicate with jumbo frames.
This involved setting the MTU in a lot of places:
- Created an untagged VLAN on a Dell N2024 and enabled jumbo frames
- Set MTU to 9000 on the vNICs for both ESXi hosts
- Set MTU on the respective vSwitches to 9000
- Within the Windows VMs, set MTU to 9000 on both NICs
I always like to check my work, especially in this case, as it isn’t something I do often. The application which would use this connection was weeks from being installed. I came across how to use ping to test here.
From the referenced link, for Windows, the format is:
ping –f –l 9000 [destinationIP]
As it has been a little while since this was done, I think I may have had to drop the MTU size to account for the ICMP header as mentioned in the link- I believe to 8972.
Anyways, when it came time to turn up the application utilizing jumbo frames, everything worked as desired.
