How to Turn Off NAT-PMP and UPnP on Your Router

A few weeks back after the disastrous distributed denial of service attack on the DNS servers was found to have been caused by insecure Internet of Things devices, Bart suggested that we turn off automatic port forwarding. This is a technology that is built into routers that allows devices (and software) inside your network to punch holes through your firewall in order to talk to the Internet. The advantage of this technology is that you don’t have to understand or even know what port forwarding is in order to get your devices and software to work. Unfortunately, we’ve learned that our IoT devices are often spectacularly insecure. For example, there are devices with hard-coded Secure Shell (SSH) usernames and passwords that were largely responsible for the denial of service attack.

This automated port forwarding I’m describing on most routers is called UPnP, and on Apple routers they use a similar protocol called NAT-PMP. Bart recommended that we turn this service off, and only open ports manually when we know why they need to be opened. I have both a Netgear router and an Apple router, so I thought it might be helpful if I posted tutorials on how to turn off UPnP via the web interface on the Netgear router, and NAT-PMP from the Airport Utility. Thanks to Allister Jenks for helping put together the instructions for turning off NAT-PMP from an iOS device for the Airport. And of course we made the tutorials with my favorite app, Clarify.

Here’s links to the three tutorials:

AirPort Firmware Update

Airport information screenI’m really lucky to know Steve’s dad, Ken. You may remember him from his video appearance entitled “Octogenarian Talks 1Password”. He’s not super technical but he is VERY motivated towards security. He works really hard to understand the risks of online computing and to do whatever he can to mitigate these risks. He’s actually a great example to us all.

A while ago, Ken wrote me a message telling me that his AirPort Extreme had a blinking amber light on it instead of a solid green light. I looked at mine, and it was blinking amber as well. I unplugged it, waited 10 seconds and plugged it back in, and the light turned green. I wondered what it was but suggested my father-in-law do the same thing. He did and he got the green light as well.
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How to Reduce the File Size of a PDF Using Preview

Ever created a PDF with images only to discover the file was huge?  Using Preview you can shrink the file easily but the quality fo the images will be dreadful.  Back in 2012, Josef Habr figured out a clever way to edit some System-level Library files to improve the quality of the images when using Preview to compress the files and posted them on http://hints.macworld.com. He spent some time coming up with some options for good, better, and best image quality too.  After he posted this, someone else pointed out that instead of editing the System Library files, you could accomplish the same thing using the ColorSync utility.  While using the ColorSync Utility is great for creating the modified filters, many have reported that you still have to move the filters into the System level Library to make them take.

Basic outline of the steps will be:

  1. Show how the default Reduce File Size option is accessed in Preview
  2. Use ColorSync Utility to create good, better and best filters
  3. Copy the newly created filters into the System level Library
  4. Verify that the new filters are available in Preview

One caution – when you reinstall or upgrade your operating system, these filters will be removed, so keep a copy of this tutorial and a copy of your filters as well so you can put them back for later use.

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Create Cute Address Labels on the Mac – New and Improved

Cute address labelSome of my most popular tutorials over the years on podfeet.com have been the ones explaining how to make address labels during the holidays. Years ago it involved using Excel to organize the labels, exporting them to a csv file, and then using Word to do a mail merge to make the labels. I remember my friend Diane and me spending HOURS getting this to work each year.

A few years ago Apple simplified everything by making it possible to print labels right from the Contacts application.
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Checklist to Limit Data Use on Travel (Updated)

Problem to be solved:

I have a shared data plan between my Mifi and my iPad. Under normal use at home I never go over my 4GB plan (not even close) but about 2 days into a vacation I get a 75% usage warning. I had Katie Floyd of the Mac Power Users Podcast on the NosillaCast Episode #448 to help me figure out the root causes and how to control my usage on travel.  These instructions are the checklist she helped me create to best manage my data. Your mileage my vary but I’m betting at least some of these ideas will help you too.

I updated this checklist in August 2015 to include new items that run automatically that could be the cause of significant data usage. In this post I recommend a tool called TripMode from tripmode.ch to monitor and limit network access by application: Can TripMode Demystify My Massive Network Data Usage?

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How to Disable Auto-Play Videos in Facebook

Recently Facebook decided that we wanted our feeds littered with auto-playing videos.  The only saving grace is that the audio doesn’t also play but it’s still distracting and annoying to many of us. Luckily, there’s a switch to turn it off from the web-version of Facebook, and in a completely different place to turn it of for iOS.  This quick tutorial will show you how to stop the madness!

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How to Uninstall VPN Server on Mac

If you’ve installed a VPN server on your Mac using Donald Burr’s most awesome instructions but for some reason want to uninstall the server, here’s an uninstall script along with text-based instructions from Donald:

Download the script here:
https://dl.dropboxusercontent.com/u/169813/uninstall-openvpn

Find the place where you downloaded the script (probably in your Downloads folder), keep a finder window open and off to the side. Open a Terminal window, and type:

chmod [space] +x [space]

DO NOT press return yet. In the Finder window, drag the script into the Terminal window, it should insert its path in the command line you are currently typing. Then press return.

Finally type this:

bash [space]

Again DO NOT press return, but drag+drop the script from Finder into the terminal, then press return. The script should run now. When it’s finished reboot your machine.

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