topic Re: Is it a necessary to change the MTU size to 1700 if I just use DFW of NSX? in VMware NSX Discussions

Is it a necessary to change the MTU size to 1700 if I just use DFW of NSX?

BlueGrass168 — Mon, 03 Oct 2022 16:12:11 GMT

Hi all,

We plan to deploy NSX DFW as second Tier firewall on the network.

We are not going to use any routing/switching technology of NSX, should I change the Distribution switch MTU to 1700 for this case?

Thanks.

Re: Is it a necessary to change the MTU size to 1700 if I just use DFW of NSX?

ukonstantin — Mon, 03 Oct 2022 16:41:43 GMT

When you still use NSX-T only for the DFW it is still not necessary to change the MTU to 1700. But anyway it is recommended for a long-term plan. Maybe if an overlay will later implemented.

regards

Udo

Re: Is it a necessary to change the MTU size to 1700 if I just use DFW of NSX?

Perttu — Thu, 06 Oct 2022 16:53:49 GMT

Hi,

Enabling jumbo frames aka setting MTU higher than 1500 on VDS is kind of an indication that jumbos are also supported in physical infrastructure as well. If it is not set there, I wouldn't change it on VDS either.

When you're choosing overlays, then you should check that all paths between TEPs in a same TZ are jumbo enabled concerning every on all intermediate switches and routers while in your control.

Re: Is it a necessary to change the MTU size to 1700 if I just use DFW of NSX?

ukonstantin — Wed, 04 Jan 2023 07:56:07 GMT

In most datacenter infrastructure environments (Cisco, Aruba etc..) the MTU Size is per default set to Jumbo frames.