Access to other guests via host considering the iptables rules

Suppose I have the following content in the /etc/network/interfaces file of a host and no other routing entries or iptables rules: auto lo iface lo inet loopback iface ens3 inet manual auto vmbr0 iface vmbr0 inet static address 1.2.3.4 netmask 255.255.255.0 gateway 1.2.3.1 bridge_ports ens3 bridge_stp off bridge_fd 0 auto vmbr1 iface vmbr1 inet static…