How do I delete network interfaces
These are for the most part physical network adapters which exist within your computer. Even if you remove them all from System Preferences --> Network, ifconfig will still report them all.

Here's the default list for a MBP 2011 17 inch:

lo0: flags=8049&lt;UP,LOOPBACK,RUNNING,MULTICAST&gt; mtu 16384
    options=3&lt;RXCSUM,TXCSUM&gt;
    inet6 ::1 prefixlen 128 
    inet 127.0.0.1 netmask 0xff000000 
    inet6 fe80::1%lo0 prefixlen 64 scopeid 0x1 
    nd6 options=1&lt;PERFORMNUD&gt;
gif0: flags=8010&lt;POINTOPOINT,MULTICAST&gt; mtu 1280
stf0: flags=0&lt;&gt; mtu 1280
en0: flags=8863&lt;UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST&gt; mtu 1500
    options=10b&lt;RXCSUM,TXCSUM,VLAN_HWTAGGING,AV&gt;
    ether c8:2a:14:33:ca:46 
    nd6 options=1&lt;PERFORMNUD&gt;
    media: autoselect (none)
    status: inactive
en1: flags=8823&lt;UP,BROADCAST,SMART,SIMPLEX,MULTICAST&gt; mtu 1500
    ether e4:ce:8f:2g:c7:aa 
    nd6 options=1&lt;PERFORMNUD&gt;
    media: autoselect (&lt;unknown type&gt;)
    status: inactive
en2: flags=963&lt;UP,BROADCAST,SMART,RUNNING,PROMISC,SIMPLEX&gt; mtu 1500
    options=60&lt;TSO4,TSO6&gt;
    ether d2:00:1d:b8:61:60 
    media: autoselect &lt;full-duplex&gt;
    status: inactive
fw0: flags=8863&lt;UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST&gt; mtu 4078
    lladdr c8:2a:14:ff:fe:cb:96:16 
    nd6 options=1&lt;PERFORMNUD&gt;
    media: autoselect &lt;full-duplex&gt;
    status: inactive
p2p0: flags=8802&lt;BROADCAST,SIMPLEX,MULTICAST&gt; mtu 2304
    ether 06:ce:8f:2f:b7:aa 
    media: autoselect
    status: inactive
bridge0: flags=8863&lt;UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST&gt; mtu 1500
    options=63&lt;RXCSUM,TXCSUM,TSO4,TSO6&gt;
    ether ca:2a:18:23:ea:00 
    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: en2 flags=3&lt;LEARNING,DISCOVER&gt;
            ifmaxaddr 0 port 6 priority 0 path cost 0
    nd6 options=1&lt;PERFORMNUD&gt;
    media: &lt;unknown type&gt;
    status: inactive
en4: flags=8863&lt;UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST&gt; mtu 1500
    options=4&lt;VLAN_MTU&gt;
    ether 08:6d:41:e6:e7:46 
    inet6 fe80::a6d:41ff:fee6:e748%en4 prefixlen 64 scopeid 0xc 
    inet 192.168.1.13 netmask 0xffffff00 broadcast 192.168.1.255
    nd6 options=1&lt;PERFORMNUD&gt;
    media: autoselect (100baseTX &lt;full-duplex,flow-control&gt;)
    status: active


I ran ifconfig both before and after deleting almost all the network connections. The results were exactly the same.

This is the default configuration with six listed interfaces



This is the default configuration with six listed interfaces



As I mentioned the ifconfig output was exactly identical whether the interfaces had been deleted or not.

If you'd like to go deeper networksetup gives you more human readable output. For instance networksetup -listallhardwareports yields:

Hardware Port: Ethernet
Device: en0
Ethernet Address: c8:2a:14:33:ca:46

Hardware Port: Apple USB Ethernet Adapter
Device: en4
Ethernet Address: 08:6d:41:e6:e7:48

Hardware Port: FireWire
Device: fw0
Ethernet Address: c8:2a:14:ff:fe:cb:96:16

Hardware Port: Wi-Fi
Device: en1
Ethernet Address: e4:ce:8f:2f:b7:aa

Hardware Port: Bluetooth PAN
Device: en3
Ethernet Address: e4:ce:8f:2f:b7:ab

Hardware Port: Thunderbolt 1
Device: en2
Ethernet Address: d2:00:1c:b9:61:60

Hardware Port: Thunderbolt Bridge
Device: bridge0
Ethernet Address: ca:2a:14:33:ea:00

VLAN Configurations


While you can't add or remove hardware ports with networksetup, you can enable and disable devices with networksetup -removepreferredwirelessnetwork &lt;device name&gt; &lt;network&gt;

You can get a full list of the available networksetup commands with man networksetup and some nice examples.

If you really want to disable the hardware completely so it doesn't show up, get out your Torx screwdrives and a solder gun. Why would someone want to do so? For the same reasons, one might disconnect iSight Camera or the microphone. If you aren't going to use an interface (particularly a wireless one), it's a constant security hasard.

For VMware and other virtual machines, you'll want to remove their .kext extensions which install virtual interfaces. While I'm on board for disconnecting microphones and video cameras, I don't think removing network interfaces would help much as your computer is vulnerable as soon as it's online. If I did want a truly secure computer, I'd make sure it simply had no networking hardware inside or on the motherboard. This probably means stepping back a few generations.

This kind of secure box should then be kept in a physically secure location. I know a lawyer with a safe room in his office where just such a computer stands. It never touches the internet or any other networking device. If he wants copy out of it, he doesn't use a removable device such as a USB card or a floppy drive. He prints. If he wants a digital version, someone scans and OCR's the printed output.