Comments
On Sat, Jun 28, 2025 at 12:49 PM Nick <atod101...@gmail.com> wrote:
> Does anyone have a document on how to accomplish this?
>
> I understand one method is using socket_vmnet, however this appears to
> utilize MacOS's DHCP server in assigning addresses. I would like to use my
> own DHCP server to assign addresses based on MAC address.
>
> I'm assuming the other configuration require will utilize either tuntap
> (Monterey) or tunnelblick (Ventura+)? /etc/pf.conf must be edited?
>
>
I found a possible solution for MacOS, which follows. I think there's
another solution, which is to invoke qemu as root with appropriate options,
appreciate any guidance on that.
I found a debug work around solution to this problem. There are two
solutions to running your own DHCP server so you can provide DHCP options
to QEMU VMs. I use socket_vmnet to create a network bridge for the HostOnly
network.
Here is my working debug configs. One is to use ISC DHCP server on the Mac,
disabling MacOS DHCP server in scripts. The other is to use the Mac
supplied DHCP server and edit some config files. It would be nice if
socket_vmnet had an option to disable the DHCP server (I tried limiting the
IP range to nothing, but it still assigns an IP and the Mac DHCP server
starts). When I finish testing I'll put a write up of this somewhere.
USE ISC DHCP SERVER:
Install
sudo port install socket_vmnet
sudo port install isc-dhcp
Configure ISC DHCP server
Start ISC DHCP server
Launch socket_vmnet
sudo socket_vmnet --vmnet-interface=bridge100 --vmnet-gateway=192.168.57.1
--vmnet-dhcp-end=192.168.57.1 /var/run/socket_vmnet
Stop DHCP server on MacOS
sudo launchctl unload -F /System/Library/LaunchDaemons/bootps.plist
Now start the VM
socket_vmnet_client /var/run/socket_vmnet qemu-system-x86_64 -accel hvf
-device virtio-net-pci,netdev=net0,mac=52:54:00:12:34:56 -netdev
socket,id=net0,fd=3 -m 8000 -drive file=debian_12-1_s0-disk1.qcow2
MAC SUPPLIED BOOTP/DHCPD:
The other option is to use the MacOS supplied DHCP server with options:
Install socket_vmnet
Configure MacOS DHCP server
cd /etc
sudo cp bootpd.plist bootpd.plist.socket_vmnet
3. Edit bootpd.plist in <subnets><array><dict> section add following:
<!-- Debian Includes These -->
<!-- Auto-Config -->
<key>dhcp_option_116</key>
<string>1</string>
<!-- Broadcast Address -->
<key>dhcp_option_28</key>
<string>192.168.57.255</string>
At the bottom change:
<key>use_server_config_for_dhcp_options</key>
<false/>
At the bottom change:
<key>use_server_config_for_dhcp_options</key>
<false/>
Edit /etc/bootptab
$ sudo cat bootptab
# bootptab
%%
# hostname hwtype hwaddr ipaddr bootfile
deb12-0 1 52:54:00:12:34:56 192.168.57.2
Start socket_vmnet per ISC config above
Stop the MacOS DHCP server
sudo cp bootpd.plist.socket_vmnet bootpd.plist && sudo launchctl unload -F
/System/Library/LaunchDaemons/bootps.plist && sudo launchctl load -F
/System/Library/LaunchDaemons/bootps.plist
Launch the VM via QEMU per above ISC config steps
If you're going to do NAT over the same interface you need to edit
/etc/pf.conf for NAT over the same interface that is on the hostonly
network. I'm still working on this but here's a debug version.
/etc/pf.conf
#
# com.apple anchor point
#
icmp_types = "echoreq"
#priv_nets = "{ 127.0.0.0/8, 192.168.57.0/24, 10.0.0.0/8 }";
set block-policy drop
set loginterface en1
set skip on lo0
scrub in all
scrub-anchor "com.apple/*"
nat-anchor "com.apple/*"
rdr-anchor "com.apple/*"
nat on en1 from bridge100:network to any -> (en1)
pass in quick on bridge100 inet from 192.168.0.0/24 to 192.168.0.10
pass out quick on en1 proto udp all keep state
pass out quick on en1 proto tcp all modulate state flags S/SA
pass in quick on bridge100 inet from 192.168.0.0/24 to 192.168.57.1
pass in quick on bridge100 inet from 192.168.0.0/24 to any keep state
pass in quick log on 192.168.57.1 all
pass in all
pass out all
dummynet-anchor "com.apple/*"
anchor "com.apple/*"
load anchor "com.apple" from "/etc/pf.anchors/com.apple"
Load it:
$ sudo pfctl -n -f /etc/pf.conf
