Transparent Firewall usando macOS pf

Sto provando a configurare un firewall trasparente con un Mac mini con macOS Sierra. Fondamentalmente sto provando a farlo (solo con macOS): Un firewall trasparente che usa OpenBSD

Questa è la mia configurazione di rete:

Internet <-ethernet-> Router <-ethernet->en0 Mac mini en4<-ethernet-> AppleTV

Il router si collega anche a molti altri dispositivi tramite Wifi.

Ora ecco cosa ho fatto su Mac mini per renderlo un firewall trasparente:

1. Ho configurato il bridge tramite questi comandi:

   sudo ifconfig bridge1 create
   sudo ifconfig bridge1 addm en0 addm en4
   sudo ifconfig bridge1 up
   

Dal punto di vista di AppleTV ora è come se il Mac mini non esistesse.

2. Ho configurato pf aggiungendo questo a /etc/pf.conf :

   anchor "org.user"
   load anchor "org.user" from "/etc/pf.anchors/org.user"
   

   e creato /etc/pf.anchors/org.user con questo contenuto:

   # skip lo0
   set skip on lo0
   
   # options
   set block-policy drop
   
   # rules
   block on en4 all
   

   Poi ho "riavviato" pf con le nuove regole:

   sudo pfctl -f /etc/pf.conf
   sudo pfctl -e
   

Ora non mi aspetto alcun traffico da AppleTV per entrare nella rete. Ma AppleTV funziona ancora come se non avessi mai impostato le regole del pf.

Cosa mi manca?

PS: ecco l'output di ifconfig:

MacMini:~ Daniel$ ifconfig
lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 16384
    options=1203<RXCSUM,TXCSUM,TXSTATUS,SW_TIMESTAMP>
    inet 127.0.0.1 netmask 0xff000000 
    inet6 ::1 prefixlen 128 
    inet6 fe80::1%lo0 prefixlen 64 scopeid 0x1 
    nd6 options=201<PERFORMNUD,DAD>
gif0: flags=8010<POINTOPOINT,MULTICAST> mtu 1280
stf0: flags=0<> mtu 1280
en0: flags=8963<UP,BROADCAST,SMART,RUNNING,PROMISC,SIMPLEX,MULTICAST> mtu 1500
    options=10b<RXCSUM,TXCSUM,VLAN_HWTAGGING,AV>
    ether a8:20:66:1e:9a:62 
    inet6 fe80::1cca:5c4b:64a7:7350%en0 prefixlen 64 secured scopeid 0x4 
    inet6 2a02:8070:a89:8f00:181c:12bc:a98c:7229 prefixlen 64 autoconf secured 
    inet6 2a02:8070:a89:8f00:d489:89da:9083:17d8 prefixlen 64 autoconf temporary 
    inet6 2a02:8070:a89:8f00::9 prefixlen 64 dynamic 
    inet 192.168.0.137 netmask 0xffffff00 broadcast 192.168.0.255
    nd6 options=201<PERFORMNUD,DAD>
    media: autoselect (1000baseT <full-duplex,flow-control,energy-efficient-ethernet>)
    status: active
en4: flags=8963<UP,BROADCAST,SMART,RUNNING,PROMISC,SIMPLEX,MULTICAST> mtu 1500
    options=b<RXCSUM,TXCSUM,VLAN_HWTAGGING>
    ether 00:23:56:1c:82:26 
    inet6 fe80::223:56ff:fe1c:8226%en4 prefixlen 64 scopeid 0x5 
    nd6 options=201<PERFORMNUD,DAD>
    media: autoselect (100baseTX <full-duplex>)
    status: active
en1: flags=8823<UP,BROADCAST,SMART,SIMPLEX,MULTICAST> mtu 1500
    ether 20:c9:d0:93:5e:f1 
    nd6 options=201<PERFORMNUD,DAD>
    media: autoselect (<unknown type>)
    status: inactive
fw0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 4078
    lladdr 00:3e:e1:ff:fe:b3:04:08 
    nd6 options=201<PERFORMNUD,DAD>
    media: autoselect <full-duplex>
    status: inactive
en3: flags=963<UP,BROADCAST,SMART,RUNNING,PROMISC,SIMPLEX> mtu 1500
    options=60<TSO4,TSO6>
    ether 32:00:1b:30:40:80 
    media: autoselect <full-duplex>
    status: inactive
bridge0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
    options=63<RXCSUM,TXCSUM,TSO4,TSO6>
    ether 32:00:1b:30:40:80 
    Configuration:
        id 0:0:0:0:0:0 priority 0 hellotime 0 fwddelay 0
        maxage 0 holdcnt 0 proto stp maxaddr 100 timeout 1200
        root id 0:0:0:0:0:0 priority 0 ifcost 0 port 0
        ipfilter disabled flags 0x2
    member: en3 flags=3<LEARNING,DISCOVER>
            ifmaxaddr 0 port 8 priority 0 path cost 0
    nd6 options=201<PERFORMNUD,DAD>
    media: <unknown type>
    status: inactive
p2p0: flags=8802<BROADCAST,SIMPLEX,MULTICAST> mtu 2304
    ether 02:c9:d0:93:5e:f1 
    media: autoselect
    status: inactive
awdl0: flags=8902<BROADCAST,PROMISC,SIMPLEX,MULTICAST> mtu 1484
    ether 8e:36:65:e0:9a:1e 
    nd6 options=201<PERFORMNUD,DAD>
    media: autoselect
    status: inactive
utun0: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> mtu 2000
    inet6 fe80::9a58:4bd5:9f77:f77a%utun0 prefixlen 64 scopeid 0xc 
    nd6 options=201<PERFORMNUD,DAD>
utun1: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> mtu 1380
    inet6 fe80::1e34:cc36:613b:1ee6%utun1 prefixlen 64 scopeid 0xf 
    nd6 options=201<PERFORMNUD,DAD>
ppp0: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> mtu 1280
    inet 10.0.1.16 --> 1.0.0.1 netmask 0xffffff00 
bridge1: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
    options=3<RXCSUM,TXCSUM>
    ether aa:20:66:e1:cb:01 
    Configuration:
        id 0:0:0:0:0:0 priority 0 hellotime 0 fwddelay 0
        maxage 0 holdcnt 0 proto stp maxaddr 100 timeout 1200
        root id 0:0:0:0:0:0 priority 0 ifcost 0 port 0
        ipfilter disabled flags 0x2
    member: en0 flags=3<LEARNING,DISCOVER>
            ifmaxaddr 0 port 4 priority 0 path cost 0
    member: en4 flags=3<LEARNING,DISCOVER>
            ifmaxaddr 0 port 5 priority 0 path cost 0
    media: autoselect
    status: active
MacMini:~ Daniel$