Comments on: Set MTU Size from the Command Line of Mac OS X

By: Ed

Ed — Tue, 15 Jan 2013 19:00:48 +0000

Thanks Ahmed, I’m like “what am I missing?!”

By: Will

Will — Mon, 14 Jan 2013 23:39:14 +0000

Whoops, thanks for catching the typo!

By: Jack Bunce

Jack Bunce — Mon, 14 Jan 2013 23:14:40 +0000

“MTU stands for Maximum Transition Unit,” No, it doesn’t!

It stands for “Maximum TransMISSION Unit”

By: Dave

Dave — Mon, 14 Jan 2013 22:20:48 +0000

For the average Mac user, indeed the GUI is simpler. But what’s faster for the advanced user; digging in preferences or a short command string?

By: Andrew

Andrew — Mon, 14 Jan 2013 22:06:33 +0000

I know this is a “how to terminal”, but is it not just as simple to do this through the GUI in the Network preferences?

At least on 10.6, 7 and 8 you go to System Preferences – Network.

Select the device you want to change (WiFi, AirPort or Ethernet usually).

Choose “Advanced…”

Select “Ethernet” tab in 10.6 and “Hardware” in 10.8.

Set “Configure:” to Manually.

Set “MTU:” to “Custom” and pick your number (it will suggest a number range for you based on the OS you are using).

By: Rich W.

Rich W. — Mon, 14 Jan 2013 21:37:00 +0000

…what Sayed Ahmed said

By: Rich W.

Rich W. — Mon, 14 Jan 2013 21:34:44 +0000

For me, typing “networksetup -getMTU” was not sufficient (on a MacBook Pro running OS X 10.8.2). Terminal instead returned a long list of acceptable networksetup commands.

So I used “networksetup -listallhardwareports” to confirm that my MacBook was device “en0″.

Then I used “networksetup -getMTU ” instead, typing:
networksetup -getMTU en0

Since this was an advanced tip, this may be common knowledge to advanced users, but others may want to be aware that they might need their device name.

networksetup -getMTU

By: Sayed Ahmed

Sayed Ahmed — Mon, 14 Jan 2013 21:29:15 +0000

The first terminal command in the example is missing the interface name part for example en0, for example it should be (networksetup -getMTU en0) in case its a macBook Air on WiFi but this en0 might differ based what port you connected to, the best way to know the ports name is go to the network utility and hit info so you can see available interfaces names.

By: Chris Quirk

Chris Quirk — Mon, 14 Jan 2013 20:42:37 +0000

If you have to keep doing this regularly, there’s something very wrong. Oh, I see, you’re using Windows.

By: Dave

Dave — Mon, 14 Jan 2013 20:18:59 +0000

I have to do this constantly in Windows to maintain a VPN connection with work. Good information to know, should I ever need it…