Disabling DHCP on an Airport Extreme Router

Disabling DHCP on an Airport Extreme Router

I’ve been testing an Airport Extreme Router and found that I couldn’t disable using it as a DHCP server. Well, actually if it’s in bridge mode it won’t be a DHCP server but I wanted it as a router, not a bridge.

I’m using what are the current Airport Extreme and Airport Utility. The Airport Utility version is 6.3.2 (632.3). The Airport Extreme shows a version of 7.7.3 (which I assume is the firmware but it just says version) and the part number is ME918LL/A. It is the current model at the time of this post (July 2014).

The three router modes are:

Available router modes
Available router modes

I wanted to use it as a NAT router but without DHCP. I already have a DHCP server I want to keep (my Synology NAS). I couldn’t really turn off DHCP but there was an easy enough way to get around this limitiation.

The short instructions are summarized in the screenshot below (details later).
Configuration to prevent DHCP addresses
1. Set a small DHCP range using IP addresses that aren’t used by the real DHCP server or any other device on the network. (Actually, it can probably duplicate another device but this is cleaner.) In the screenshot I used to I had to use two addresses, the same beginning and ending addresses weren’t allowed.
2. Create dummy DHCP reservations for each of the IP addresses. The MAC addresses don’t have to be real.

Detailed Instructions

  1. Open the Airport Extreme Utility and go to the Network tab and click the Network Options button.
    Airport Extreme network tab
  2. Set a DHCP range that’s appropriate for your network. Use addresses that aren’t used by any of your computers or other DHCP ranges. (In theory none of these addresses should be used, but keeping things valid will avoid problems.) Save the screen and you’ll be back on the network tab.
    DHCP range
  3. Click the “+” sign under “DHCP Reservations.
    Click the + to add the DHCP reservations
  4. Type in a description, make sure “MAC Address” is selected for “Reserve Address By” and type an dummy Mac address. I just type the number “1” (or 2) until it stops me. Then save the information.
    Screenshot of the DHCP reservation
  5. Repeat step 4 for all IPs in the DHCP range. The Airport Utility will prefill an unreserved IP in the range so you don’t need to keep track.
  6. Save everything all the way out and your Airport Extreme will restart.

In the end the Airport Extreme is still running a DHCP server, except it doesn’t have any IP addresses to hand out so the “real” DHCP will be the only one to respond.

Backblaze Backup Review

Backblaze LogoI was doing my yearly backup review and decided to take a look at Backblaze. Backblaze is popular among Mac users although they also have a Windows client. I took a look at the Mac version.

Backblaze – The Basics

Backblaze is cloud backup. They offer “unlimited” backup but there are restrictions if not limitations. Pricing is $5 per month but is discounted for 1 year ($50) and 2 years ($95) prepaid commitments. Pricing is per computer.

Only locally attached disks can be backed up. This obviously includes internal drives and also includes firewire, USB and Thunderbolt attached drives. Network attached drives are not backed up.

There is a long list of folders on my Mac that cannot be backed up, even if I wanted to. The important ones in this list are “Applications” and “Library” (the system-wide library folder). So Backblaze cannot be used as a full system backup. On the positive side, everything that would be specific to a user can be backed up.

There’s also a long list of file types that are not backed by default although these exclusions can be removed:

wab~, vmc, vhd, vo1, vo2, vsv, vud, iso, dmg, sparseimage, sys, cab, exe, msi, dll, dl_, wim, ost, o, qtch, log, ithmb, vmdk, vmem, vmsd, vmsn, vmx, vmxf, menudata, appicon, appinfo, pva, pvs, pvi, pvm, fdd, hds, drk, mem, nvram, hdd

On the Mac you may want to be sure sparseimage files are backed up depending on how you use them. I kept virtual machine images excluded because I didn’t want to use the bandwidth to backup constantly changing files. I did remove the ISO exclusion since any ISOs I have don’t change once they’re backed up.

Backblaze will delete files from cloud storage 30 days after they’re deleted from the computer. If a external drive is disconnected from the computer (or turned off) the files will be deleted from the backup after 30 days. I wasn’t able to test this during the trial period but it appears there’s now a warning message a couple weeks before the files from the external drive are deleted.

In a true “trust no one” philosophy I can set my own encryption key. (I do have to trust that the Backblaze software is not secretly sending them my encryption key.) If I lose this key I lose all ability to restore the files and Backblaze can’t get them back. Despite this risk I require this for all my cloud storage that contains my financial and confidential records and keep the key in multiple locations.

Backblaze Trial

I took advantage of their two week trial to take a look at the Backblaze software and service. The registration, download and installation was straightforward so I won’t repeat it here. Once installed it began backing up using the default settings.

Backblaze installs itself as a preference pane. The options are (click any image for full size)…

The Main Panel

Backblaze main panelThe main panel gives you an overview of where you stand with backups. By default Backblaze will continuously backup changed files. Clicking the settings button will display six configuration screens.


Backblaze settings panelThe computers online name is automatically generated and is based on the Mac’s name. I have only one drive so it’s the temporary data drive. I changed the warning from the default 7 days to 1 day. If it’s failing I want to know right away.

Any attached hard drives are listed. Check the ones you want included, uncheck the ones that you don’t.


Backblaze performance panelPerformance lets you throttle the bandwidth used during the backup. I found the Automatic setting worked well. The estimates varied widely during my first backup so the estimate seems to be based on a narrow slice of time. I had no problem streaming Amazon or Netflix while the backup was uploading. This isn’t too surprising since the data is going in opposite directions. The uploads did slow down during the streaming.


Backblaze schedule panelNothing much here. I used “Continuously.”


Backblaze exclusions panelThe folders can’t be removed from the exclusion list but you can add other folders to exclude. I left the folders as is but I did remove DMG, ISO and SparseImage files from the file type exclusions.


Backblaze security panelThis panel is primarily informational but it’s also where I entered my private encryption key.


There’s three report panels that are informational.


Backblaze restore panelThe restore panel is informational and shows the three restore options.

Web Restore Test

Naturally, a backup is no good if you can’t restore the files. So I went through the process of a web restore. It’s a straight-forward process, although a web restore may not be well suited to restoring gigabytes of data. I only picked a couple files for the restore and they were ready in a matter of minutes.

You do have to enter your encryption key on the restore web page. So you have to again trust that Backblaze won’t remember your encryption key. You also need to trust that there’s no coding errors that will compromise the key. This is probably an acceptable risk for most people. It also seems that the files are decrypted on the server side before they are put into the zip file. It’s also seems that if you request that the files be sent to you on disk that they’ll be sent already unencrypted on the disk which seems like a bigger risk.

The web restore process is shows in the following screenshots.

Wrapping Up

Backblaze is a nice easy to use Backup service. It shares similar limitations to other “all you can eat for one price” backup services. I can see why it’s so popular but I’d prefer a backup service that can be used for long term storage without having to worry about whether or not the drive is still connected. So this became a non-starter for me.

The service is designed to backup data. I didn’t try restoring any complete OS X package files. For example, a Bento database. In the case of iPhoto and Aperture libraries (which are also library files) Backblaze will look into the library and backup the photos. But it won’t backup thumbnails. While not backing up thumbnails isn’t a problem, this less than everything approach does concern me. I’m more comfortable when I know exactly what’s happening with my backups.

The low price of Backblaze backup and ease of use will appeal to most people and for good reason.


  • Low Cost
  • Easy to Use
  • Fast backup (no throttling noticed – limitation seemed to be my connection)


  • Web restore cumbersome for large restores
  • Large restores (beyond web capabilities) costly and delayed by shipping.
  • Private encryption key has some potential holes (required before restore so files are shipped unencrypted or stored unencrypted on the Backblaze server)

Pro/Con (depends on your point of view)

  • Like all cloud backups, potentially limited by your internet connection for both speeds and data caps.
  • Not a full disk backup, still need a second backup solution for a full system.
  • Deletes backed up files 30 days after the local files vanish.


Maestro Monday: Start Scanner App

I hate having software running when it’s not needed. I also hate always having to manually start and stop software based on some often repeated action.

I recently bought a ScanSnap scanner and the ScanSnap manager needs to run whenever I want to scan. Using Keyboard Maestro’s ability to react to USB devices being connected or disconnected I was able to manage this automatically rather than leaving the software always running, or having to manually run it. What’s cool is that the ScanSnap S1300i turns on when the cover is opened (and shuts off when it’s closed) and Keyboard Maestro sees the on/off as the connection (or disconnection) based on the cover opening and closing. It’s not the actual cable connection being detected.

Hint: Activate the USB device when setting up the trigger and it will put the name of the newly connected device into the name field.

Start ScanSnap Manager

Keyboard Maestro Macro to start ScanSnap Manager

Stop ScanSnap Manager

Keyboard Maestro Macro to stop ScanSnap Manager

OS X Update 10.9.4

Apple release a Mavericks update today – OS X 10.9.4 today. While this update ended up being problem free for my Mac Mini, it had it’s scary moments. The update failed to display anything on my screen after the reboot for what seemed like eternity, but was probably more like 90 seconds to two minutes. Then it intermittently began to display what looked like the Apple logo but mostly shifted off screen, this lasted for another minute or two. Finally it displayed the typical updating message. The progress bar moved in spurts, rather than smoothly.

But eventually it finished and my Mac Mini seems normal.

When I went to update my MacBook Pro this evening the download was so slow, estimates alternated between 8 and 10 hours for the 283MB download, that I canceled it. So my laptop remains unpatched.

The update contains a startup screen fix. While I’d never seen it before, maybe this was the problem I saw, or the fix being applied. It also contain a wi-fi fix although I haven’t had any wi-fi connectivity problems. Safari was also update to version 7.0.5 and there’s a wake from sleep fix.

There’s not the typical “additional stability fixes and updates” clause and this update was quit small, only 283MB for me. The security bulletin doesn’t list anything for this update although since this bulletin usually lags behind the update it’s hard to know if it’s a lack of content or just the usual delay. Although no doubt Safari has security fixes.

Screenshot of the 10.9.4 update

Maestro Monday: Macro Libraries

The macro library is a great resource in keyboard Maestro. It was immediately obvious to me since there’s already macros loaded into the Keyboard Maestro main window.

Selecting Windows -> Macro Library from the menu displays a popup window of dozens of pre-built macros that are ready to use. Just double click the one(s) you want and they’ll be added to your active macro library where you can use it as-is or edit it to meet your needs.

The Macro Library window
The macro library window (left) is shown next to the active macros window. The “Automatically Resume Safari’s Last Session” macro has just been added from the library

Maestro Monday: Paste as Plain Text

Many Mac apps have a command “Paste and Match Style” or “Paste as Text” while many others don’t, or if they do they keyboard shortcuts are different. I paste as plain text a lot. So I have a Keyboard Maestro macro assigned to take care of it, and I assigned the macro to the <Command>-<Option>-<V> key combination.

It’s a very simple macro but one I find is a huge time saver.

Screenshot of the Paste as Plain text macroThe macro is triggered only by the key combination and used the Keyboard Maestro variable %CurrentClipboard% to get the current contents and the set them right back as plain text.

Maestro Monday: Syncing Macros

I have two Macs, a Mac Mini desktop and a laptop. Keyboard Maestro makes it easy to sync Macros between these two Macs. You’ll need a syncing service such as Dropbox. There’s no technical or compatibility requirements, it’s just a simple file sync. I use Cloud Station from my Synology NAS.

To set up Syncing first pick the Mac that has all the Macros that you want to sync. Start the Keyboard Maestro editor and pick File -> Start Syncing Macros… from the menu.

Syncing setup dialogFor the first Mac select “New”. For future Macs select “Open Existing…”. The difference is fairly obvious. For “Create New…” you’ll pick the sync file location and the existing macros will be saved to it. For “Open Existing” you’ll browse to the existing file. For “Open Existing” all existing macros will be replaced with the ones in the sync file.

That’s all there is to it, syncing will occur automatically. Syncing, in my experience, is nearly immediate and does not wait for a new macro to be completed.

Since there are differences between my two Macs I don’t want every macro to run on them both. While the macro can be written to recognize the computer it can run on, the easiest way is to create macro groups and disable the group for the Mac it should ignore.

Macro group settings screenshot

Maestro Monday: Activate an App

Another simple, easy macro for Keyboard Maestro this week. I have several apps I want to quickly switch to during the day. And I want to do this without having my hands leave the keyboard or tab between many apps. So Keyboard Maestro is used.

It’s simply a macro assigned a hot key trigger which then switches to the app. OmniFocus is the example used.

Screenshot of the activate app Keyboard Maestro macro

Maestro Monday: Keep Required Apps Running

My Mac Mini is an always on machine and there’s some apps I always want running, even when I’m not home. Keyboard Maestro makes this happen rather easily. The macro below keeps Mail, OmniFocus and Evernote open. There’s nothing difficult here.

Macro to keep required apps running

Since the macro checks for the app to be running before doing anything I’m not interrupted if I’m working at the computer, unless of course one of the apps has closed down. In that case I wouldn’t mind the interruption.


Maestro Monday: Backup OS X Contacts

This week’s Maestro macro is entirely self-contained, no Apple Script or external utilities needed. The macro exports the OS X Contact list (aka Address Book) to a file that can be imported later if it’s needed. The two restrictions are that the screen cannot be locked when the script runs and it can only be run once per day. The macro runs on Mavericks, it may need to be changed for earlier versions (for example, when “Contacts” was called “Address Book”).

I set this macro to be triggered only from the status menu. I have a regular weekly backup routine and run it at that time. While I prefer automated backup solutions, having to be at the computer to trigger isn’t a problem in this case. My weekly routing includes making sure the backups ran OK and this one runs so quickly it adds almost no time to how long it would take to verify the backup. Plus if I make a lot of changes I can easily do an immediate backup.

This script is one of the longer ones when measured by screen real estate. The process is straight-forward: Start contacts if needed, export the contacts using the export menu, change the location to where I want it and save the file, then quit contacts. There are some pauses in there to give the app time to respond.

The export command automatically includes the date in the file name so the file will have a unique name every day. If the macro is run twice in one day it will break. It will prompt to replace the file and the remaining shutdown command will be lost. This hasn’t been a problem for me so I haven’t taken the time to create a workaround.

Screen capture of macro to backup OS X contacts