$ cat /etc/hostname.vether0
inet 172.16.1.5 255.255.255.0

--------------------------------------------
$ cat /etc/hostname.bridge0
add vether0

--------------------------------------------
$ doas cat /etc/dhcpd.conf
# Local VM Subnet
subnet 172.16.1.0 netmask 255.255.255.0 {
  option domain-name "vmm.openbsd.local";
  option  domain-name-servers 8.8.8.8, 8.8.4.4;
  option routers 172.16.1.5;
  range 172.16.1.100 172.16.1.200;
}
#Alpine
host static-client {
  hardware ethernet fe:e1:bb:d1:b0:f7;
  fixed-address 172.16.1.104;
}

--------------------------------------------
$ cat /etc/vm.conf
switch "local" {
        interface bridge0
}

--------------------------------------------
doas cat /etc/pf.conf
#       $OpenBSD: pf.conf,v 1.55 2017/12/03 20:40:04 sthen Exp $
#
# See pf.conf(5) and /etc/examples/pf.conf

#original config
set skip on lo
block return    # block stateless traffic
pass            # establish keep-state

# By default, do not permit remote connections to X11
block return in on ! lo0 proto tcp to port 6000:6010

# Port build user does not need network
block return out log proto {tcp udp} user _pbuild
#/original

# VMM
ext_if="eth0"
vmd_if="{ vether0 bridge0 }"

set block-policy drop
set loginterface egress
match in all scrub (no-df random-id max-mss 1440)
match out on egress inet from !(egress:network) to any nat-to (egress:0)
pass out quick inet
pass in on $vmd_if inet
pass in on egress inet proto tcp from any to (egress) port 22

#match out on $ext_if from $vmd_if:network to any nat-to ($ext_if)
#/VMM