What are these ifconfig interfaces on macOS

Question

I have a MacBook Pro 15" 2018 (Touch Bar). I see it has a lot of network interfaces. I would like to know what they are/what they do. I did some research but I couldn't really figure out all of them, here are their SCNetworkInterfaceInfo.UserDefinedName with information I was able to find from this answer:

• ap1: ?
• awdl0: ?
• llw0: ?
• utun0: ?
• utun1: ?
• lo0: loopback (localhost)
• gif0: Software Network Interface
• stf0: 6to4 tunnel interface
• en0: physical wireless
• en1: Thunderbolt 1
• en2: Thunderbolt 2
• en3: Thunderbolt 3
• en4: Thunderbolt 4
• en5: iBridge / Apple T2 Controller
• en6: Bluetooth PAN
• en8: iPhone USB
• en9: VM network interface
• en10: iPad
• bridge0: Thunderbolt Bridge

The search engine for the Unix & Linux StackExchange is offline as of the time I'm posting this question. Thanks in advance.

lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 16384
gif0: flags=8010<POINTOPOINT,MULTICAST> mtu 1280
stf0: flags=0<> mtu 1280
en5: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
    status: active
ap1: flags=8802<BROADCAST,SIMPLEX,MULTICAST> mtu 1500
    status: inactive
en0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
    status: active
en3: flags=8963<UP,BROADCAST,SMART,RUNNING,PROMISC,SIMPLEX,MULTICAST> mtu 1500
    status: inactive
en4: flags=8963<UP,BROADCAST,SMART,RUNNING,PROMISC,SIMPLEX,MULTICAST> mtu 1500
    status: inactive
en1: flags=8963<UP,BROADCAST,SMART,RUNNING,PROMISC,SIMPLEX,MULTICAST> mtu 1500
    status: inactive
en2: flags=8963<UP,BROADCAST,SMART,RUNNING,PROMISC,SIMPLEX,MULTICAST> mtu 1500
    status: inactive
bridge0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
    options=63<RXCSUM,TXCSUM,TSO4,TSO6>
    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 0x0
    member: en1 flags=3<LEARNING,DISCOVER>
            ifmaxaddr 0 port 9 priority 0 path cost 0
    member: en2 flags=3<LEARNING,DISCOVER>
            ifmaxaddr 0 port 10 priority 0 path cost 0
    member: en3 flags=3<LEARNING,DISCOVER>
            ifmaxaddr 0 port 7 priority 0 path cost 0
    member: en4 flags=3<LEARNING,DISCOVER>
            ifmaxaddr 0 port 8 priority 0 path cost 0
    nd6 options=201<PERFORMNUD,DAD>
    status: inactive
awdl0: flags=8943<UP,BROADCAST,RUNNING,PROMISC,SIMPLEX,MULTICAST> mtu 1500
    status: active
llw0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
    status: active
utun0: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> mtu 1380
utun1: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> mtu 2000
en10: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
    status: active
en8: flags=8822<BROADCAST,SMART,SIMPLEX,MULTICAST> mtu 1500
    status: inactive

Solution

For the ones that you don't have:

• ap1: Access Point. This is used if you are using your MacBook as a wireless host where you are sharing its connection.

• awdl0: Apple Wireless Direct Link. WIFI p2p connection for things like AirDrop, Airplay, etc. Also used for Bluetooth.

• llw0: Low-latency WLAN Interface. Used by the Skywalk system.

• utun0: Tunneling interface. Used for VPN connections to tunnel traffic or for software like Back To My Mack.

• utun1: Same as utun01

Comments

[Velociround]

Could you please elaborate a bit on these, too? Although I have their names and I'm guessing what they do, I would like to know for sure: gif0, stf0, en9: VM network interface, bridge0: Thunderbolt Bridge. Thank you very much