At first

Because the kernel module br_netfilter is enabled on Debian 10 Buster Packets did not come out of the bridge just by making a bridge normally Make a note of the settings that allow packets to pass outside the bridge.

reference

https://manpages.debian.org/buster/systemd/sysctl.d.5.en.html

Setup steps

Force the `br_netfilter` module to load at startup.

If you do not make this setting, the setting contents of the next procedure will not be reflected.

`bash:/etc/modules-load.d/bridge.conf`


br_netfilter

Disable packet filtering in the bridge.

`bash:/etc/sysctl.d/bridge.conf`


net.bridge.bridge-nf-call-ip6tables = 0
net.bridge.bridge-nf-call-iptables = 0
net.bridge.bridge-nf-call-arptables = 0

restart.

# reboot

Disable br_netfilter on Debian Buster