When is a switch not a switch?

[Patrick M. Hausen]

Hi all,

> Am 20.10.2020 um 11:28 schrieb D'Arcy Cain <darcy at druid.net>:
> 
> On 10/20/20 4:36 AM, Patrick M. Hausen wrote:
>> It's officially documented here:
>> https://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/network-bridging.html
> 
> I did see that.  Does that mean that I don't even need to create switches at all?

What is a switch in this context? I use bridge interfaces to connect jails via epair
and VMs via tap.

>> "If the bridge host needs an IP address, set it on the bridge interface, not on the member interfaces."
> 
> But I don't necessarily need an IP on the bridge itself, right?

Depends ;-)

If the host has got e.g. em0 with an IP address and you want to make
that physical interface part of e.g. bridge0 as well as all the VMs so they
can communicate on the wire ...

you *must* move the IP address config from em0 to bridge0 and
configure em0 "up".

If em0 does not have an IP address on the host and should be used
exclusively for VMs, then the bridge does not need an IP address, either.
Still you need to configure em0 "up".

And additionally ...

- you should disable all hardware acceleration features on the physical interface
- if you are using pf you should move the rule processing from the members to the bridge like so:

sysctl net.link.bridge.pfil_member=0
sysctl net.link.bridge.pfil_bridge=1


HTH,
Patrick
--
punkt.de GmbH
Patrick M. Hausen
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