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We've got a Macbook Air (Actually, we've got some Airs, Some Pros and some iMacs). We've got a consistently annoying problem, which is that when they connect to our DHCP server, they've actually got 2 different IP addresses, and that causes 2 different IP addresses to get set in our DHCP lease file, as well as 2 in our DNS (automagically updated).

On linux workstations with multiple NICs, we bond/team them into bond0 and set the MAC address by hand to be equal to one of the NICs in the bond. This pretty much fixes all the associated ballache.

I just tried to bond the NICs on the Air, using Manage Virtual Interfaces (Advanced settings in Networking, under the little gearwheel in the Adaptors list). I could add eth0 (the USB Ethernet dongle) to the bond just fine, but the wireless Airport adapter didn't show up.

Is it not possible to bridge across the interfaces in this way?

Is there another way to do it?

Are we crazy for wanting to do it this way? Is there a better way?

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IIRC the MTU has to be the same on all lagg interfaces. Not sure of other ways. Definitely not crazy, I do this on my fBSD laptop for the same reason, that and it can "roam" seamlessly from wired to wireless. – Chris S Feb 15 '12 at 15:26
That's pretty much what we're hoping to achieve. – Tom O'Connor Feb 15 '12 at 15:30
up vote 1 down vote accepted

Unfortunately, to the best of my knowledge, no Wi-Fi card used by Apple in a Mac has ever supported LACP. Using the terminal you can easily confirm whether or not your various interfaces can be aggregated with the following command: networksetup -isBondSupported (interface)

In my case, using a Mid-2010 MacBook Pro running 10.7, I get the following:

$ networksetup -isBondSupported en0
$ networksetup -isBondSupported en1

Where en0 is Ethernet and en1 is AirPort.

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You may be a little crazy for wanting this...I guess I never saw it as a problem. For my Mac users, the network interface priority is Ethernet > Wireless. For most users in the office, they'll pickup wireless. If they physically plug in, the Ethernet connection takes over. Is there any reason your users switch back and forth? In my environment, the wireless network has shorter lease times and the DNS records are scavenged... but what is the exact problem? The presence of duplicate entries?

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Having this encourages users to plug into ethernet, knowing they can pick up their laptop and go to a meeting without losing active connections. Without this everyone saturates the wireless network. – rox0r Jan 22 '13 at 17:30
How would they saturate the wifi network? – ewwhite Jan 22 '13 at 17:32
It depends on your network, but having switched gigabit ethernet far surpasses having a high density of developers on wireless. – rox0r Jan 22 '13 at 17:35

I looked into just this issue a year or two ago (OS 10.6.x IIRC) and found that bonding across interfaces was a driver-level limitation in either the wireless driver or the ethernet driver, I can't remember which, and could only be done with expensive 3rd party software. Looks like it may have been fixed in 10.7 per (which only talks about eth, but may be able to handle wireless too, though you might have to drop down to the terminal to enable it)

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