Unexpected interfaces in ifconfig In the middle of installing a tool called mrtg, I bailed out from a perl script to set various configuration parameters for use of snmp because it became clear that I had no idea what I was doing.  I also explored some snmp commands myself, but didn't keep a record, unfortunately.

I come back to ifconfig and notice it shows three new interfaces (not there just before the previous adventure):

gif0: flags=8010&lt;POINTOPOINT,MULTICAST&gt; mtu 1280
stf0: flags=0&lt;&gt; mtu 1280
fw0: flags=8863&lt;UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST&gt; mtu 4078
    lladdr 60:fb:42:ff:fe:f4:cd:9e 
    media: autoselect &lt;full-duplex&gt;
    status: inactive


My laptop on the same LAN has a different new interface called p2p0 that I hadn't noticed before, as well as gif0 and stf0 but not fw0.

After I reset my Airport Extreme to factory default, and reinstalled OS X Lion on my machine, with a wiped disk, they are still there.  This:

sudo ifconfig gif0 destroy


makes gif0 go away, but on reboot it comes back.  There is a previous answer with some info but what I'd like to know is why are they still there despite a clean install, could they be a security risk, and should I or can I make them go away.  Should I be looking at the Airport or something in my StartupItems?

UPDATE:  Does my machine set these up at boot or does the Airport remember them?  And in either case, why didn't a clean install (or factory reset) restore them to the previous configuration?
fw0 is the FireWire network interface. It's benign.

stf0 is an IPv6 to IPv4 tunnel interface. It's a bridge connection that exists to help us transition from IPv4 to the IPv6 standard. It's benign. You can read more about it here if you like: http://en.wikipedia.org/wiki/6to4

gif0 is a generic tunnel interface. It's used to tunnel IPv4 traffic to an IPv6 network and back. It's benign. You can read more about it here: http://www.gsp.com/cgi-bin/man.cgi?section=4&amp;topic=gif