OPNsense Forum

Archive => 20.7 Legacy Series => Topic started by: dcol on September 29, 2020, 02:07:28 am

Title: Advice with bridge setup using two switches
Post by: dcol on September 29, 2020, 02:07:28 am

I would like to setup two networks from 2 switches and bridge them. One managed with SPF+ ports using 9000 MTU devices. The other unmanaged with 1GB Ethernet ports connected to devices using 1500 MTU.

Is the best option to just bridge the two switches in OPNsense using two interfaces? I need the systems on the SPF switch to handle large media files, which is why I need Jumbo Frames. But I know it is not wise to mix MTU, so I am looking for the best options here.

Title: Re: Advice with bridge setup using two switches
Post by: dcol on September 29, 2020, 05:41:20 pm

Bump....Anyone?

Title: Re: Advice with bridge setup using two switches
Post by: Patrick M. Hausen on September 29, 2020, 08:06:37 pm

To my knowledge you cannot bridge two different MTUs. You need to route between the networks so fragmentation can occur.

Title: Re: Advice with bridge setup using two switches
Post by: dcol on September 29, 2020, 08:34:03 pm

I suppose another option then is to isolate the two switches and use a separate NIC for systems needing connections like internet access in the 1G switch.

Title: Re: Advice with bridge setup using two switches
Post by: dcol on September 30, 2020, 01:43:41 am

I found a workable solution.
I created a new interface with 9000 MTU and connected it to the SPF+ managed switch. All the 1G devices connect to an unmanaged switch to a different interface port at 1500 MTU.

I will let OPNsense route the higher MTU traffic to the the lower MTU devices.

If this is not a good solution, please advise. Thank you.