+-----------------------------------------------------------------------
| Running avahi on OpenBSD
+-----------------------------------------------------------------------

For proper functionality, multicast(4) needs to be enabled. To do so,
add the following line to /etc/rc.conf.local(8):
    multicast=YES

Note that you MUST have a system-wide D-BUS daemon running BEFORE
starting avahi, e.g.:
    rcctl enable messagebus avahi_daemon
    rcctl order messagebus avahi_daemon

A rule similar to the one below can be used in pf.conf(5) to pass
incoming avahi (multicast) traffic:
    pass proto udp from any to 224.0.0.251 port mdns allow-opts
    pass inet6 proto udp from any to ff02::fb port mdns allow-opts

for SSDP:
    pass proto udp from any to 239.255.255.250 port ssdp allow-opts
    pass inet6 proto udp from any to { ff02::c, ff05::c, ff08::c } port ssdp allow-opts
