Hypervisor.framework

The drivers utilized on MacOS, specifically HyperKit and QEMU, rely on MacOS' Hypervisor.framework to manage the networking stack for the instances. When an instance is created, the Hypervisor.framework on the host employs MacOS' 'Internet Sharing' mechanism to establish a virtual switch. Each instance is then connected to this switch with a subnet address from:

$ sudo cat /Library/preferences/SystemConfiguration/com.apple.vmnet.plist | grep -A1 Shared_Net_Address
Password:
	<key>Shared_Net_Address</key>
	<string>192.168.65.1</string>

Furthermore, the host provides DHCP and DNS resolution services on this switch through the IP address 192.168.65.1, facilitated by the bootpd and mDNSResponder services running on the host machine. It is worth noting that attempting to manually edit the configuration file /etc/bootpd.plist is futile, as MacOS will regenerate it according to its own preferences.

Is the bootpd DHCP server alive?

sudo lsof -iUDP:67 -n -P

Start it:

sudo launchctl load -w /System/Library/LaunchDaemons/bootps.plist

Flush all DHCP leases:

sudo launchctl stop com.apple.bootpd
sudo rm -f /var/db/dhcpd_leases
sudo launchctl start com.apple.bootpd

It appears that at a certain juncture, docker and multipass ceased to share the same network bridge. Whichever starts first will occupy bridge100 with the IP address 192.168.64.1, while the subsequent one will take bridge101 with the IP address 192.168.65.1. Upon repeatedly stopping and starting these services, you will notice a sequential increment in the third octet of the Shared_Net_Address.