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I have a 2019 iMac (running Big Sur)with three physical Ethernet ports; one is the built-in port and two more are located on Thunderbolt devices I have attached.

When I run ifconfig, I get two whole screens full of interfaces, and I'd like to know what they are.

I have Parallels installed, which adds some more virtual interfaces. I also found this question which explains a few more of them. But I'd like some help understanding what all these interfaces are:

  • lo0 -- The loopback interface
  • gif0 -- The linked article says it's a "software interface" but that's pretty hand-wavey
  • stf0 -- 6-to-4 interface (for IPv6 <-> IPv4 tunneling)
  • en0 -- Built-in Ethernet port
  • en1 -- Built-in WiFi
  • en5 and en6 -- These are the two external Ethernet ports
  • ap1 -- ???
  • awdl0 -- Apple Wireless Direct Link (Apple's own flavor of the WiFi Direct protocol; used for AirPlay, AirDrop, HomeKit, GameKit, iOS Bluetooth tethering, etc.)
  • llw0 -- ???
  • bridge0 -- Internet connection sharing, perhaps?
  • bridge100 -- Parallels 'Shared Network' adapter
  • utun0 and utun1 -- Linked article says these are for Find My Mac, but I don't have that turned on, and why are there two of these?

That leaves us with en2, en3 and en7. I'm pretty sure 'en7' is the Parallels 'Host Only' adapter (it's the only one that has the promiscuous mode flag set), but I have no idea what the other two could be. Also, what ever happened to en4?

Some help understanding all these would be appreciated.

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  • One question per question is best. Want to narrow down this to one that’s not covered on the general, are all these OK? Yours are all OK, too – bmike Dec 11 '20 at 2:05

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