Category: IT

Mac OS X Server: Prevent “missing Bluetooth keyboard” startup interruption

Sometimes, it may seem convenient to quickly connect a Bluetooth keyboard and a Bluetooth mouse to a Mac OS X Server machine for administration. The not so intuitive consequence of this however is, that at future startups, if there’s no keyboard or mouse connected to the machine (which is the common case with servers), Mac OS X will by default fall back to searching for that once connected Bluetooth keyboard or mouse and even stops booting when it doesn’t find them.

In order to prevent this, do the following on your Mac OS X Server:

  1. Open Bluetooth Preferences
  2. Disconnect and remove any associated Bluetooth devices
  3. Click the “Advanced…” button
  4. In the advanced Bluetooth settings, deselect both “Open Bluetooth Setup Assistant at startup if no keyboard is detected” and “Open Bluetooth Setup Assistant at startup if no mouse or trackpad is detected”
  5. Unless really needed, disable Bluetooth on a server. So, better grab a USB keyboard and mouse next time you need to do some admin ;)

Screen Shot 2014-06-24 at 13.43.52

Screen Shot 2014-06-24 at 13.44.40

macvim – Vim for the Mac

When using Mac OS X, I used to use the CLI vim by the excellent Homebrew package manager.

Now I’ve just stumbled over macvim, which is kind of a “deluxe vim” for Mac OS X, including adjusted key bindings for the Mac and a GUI menu, supporting Cocoa file dialogs, among others.

It’s highly recommended if you want to have the best of both the CLI and GUI editor worlds.


Zimbra ZCS: OpenDKIM not running

After upgrading Debian, OpenDKIM sometimes stops running or fails to properly restart. If you don’t actively monitor your ZCS server, the only way to detect this is either through a growing mail queue of unsent messages or through a note in the ZCS server admin panel.

Usually, manually restarting either OpenDKIM itself or the whole ZCS server once “fixes” the problem:

# service zimbra restart


# /etc/init.d/zimbra restart

In other cases, fixing the permissions may help:

# /opt/zimbra/libexec/zmfixperms -verbose -extended


Some helpful Git resources

A friend recently told the following joke:

“The idea that git can be used offline is an illusion – you still need connectivity for googling which arguments to pass to what command.”

That’s an exaggeration, of course, but as always, there’s a grain of truth in it. So here we go:

Delete duplicate e-mail messages

If you need to delete duplicate e-mail messages on an IMAP server, take a look at this useful IMAP de-duplicator script:

IMAP de-duplicator – IMAPdedup

As IMAPdedup is a command line interface tool (a python script), it’s particularly useful for:

  • automated deletion of duplicates (as it can be called from other scripts)
  • extraordinarily big mailboxes or if you have many subfolders (as there’s no intervention by the user required)
  • if you have console/shell access to the IMAP server (as you can then run the script on the server itself, speeding the de-duplication process further up)

I also found that it deals relatively well with failures (e.g. when a folder is read-only and hence messages can’t be deleted): It simply reports them on the screen and carries on.

Here’s a quick’n’dirty bash script to de-dup the inbox and all subfolders of the specified account:

# Delete all duplicate messages in all folders of said account.
# Note that we connect through SSL (-x) to the default port.


for folder in ` -s $SERVER -x -u $USER -w $PASS -l`;
do -s $SERVER -x -u $USER -w $PASS $folder

If you only have to de-duplicate messages in a small folder, you could also use the following de-duplication add-on for Mozilla Thunderbird:

Remove Duplicate Messages Add-on for Thunderbird

Note however that the ‘Remove Duplicate Messages’ add-on is intended for interactive use only, not for batch processing. I also noticed that it fails at cleaning big mail folders (e.g. containing 50’000 messages).


Moving Zimbra Collaboration Server to a new IP address

Here’s a quick overview how to migrate a ZCS mail server (based on Ubuntu) to a new IP address:

0) Not covered here: Adjusting DNS entries. Make sure you lower the TTLs of the relevant DNS entries a couple of days in advance in order to minimize downtime for clients (e.g. set a TTL of 300 for a 5 minute downtime).

1) Set the new IP address in:
* The relevant DNS entries
* /etc/network/interfaces
* /etc/hosts
* If ZCS runs in a container/VM, don’t forget to adjust its IP address too.

2) If the new IP address is part of a new subnet, make sure to add this new subnet to ZCS’s trusted_networks, otherwise, sending (relaying) messages through ZCS from Zimbra Desktop (or any other mail client) won’t work[1]. This can be set using ZCS’s web admin interface (i.e.
Navigate to “Server settings”, then open the “MTA” tab and set something analogous to the following in “MTA Trusted Networks”: w.x.y.z/26

3) Restart networking and the ZCS services (it’s important, as this adjusts the trusted_network setting in ZCS’s amavisd too):
# /etc/init.d/zimbra stop
# /etc/init.d/networking restart
# /etc/init.d/zimbra start

Alternatively, just reboot the server, particularly if it runs in a VM.


Note: The need for the adjustments in step 2) might come as a surprise. Authenticated messages to be relayed through ZCS apparently seem to originate from the external IP address, not localhost/

[1] A typical postfix error message might look like:
Delivery Failure Notification: Invalid address: somebody . com.zimbra.cs.mailbox.MailSender$SafeSendFailedException: MESSAGE_NOT_DELIVERED; chained exception is: com.zimbra.cs.mailclient.smtp.InvalidRecipientException: RCPT failed: Invalid recipient 554 5.7.1 : Relay access denied

iTerm2 – Mac OS Terminal Replacement

iTerm2, the successor of iTerm, seems to be quite a bit better then the default Mac OS X terminal app:

iTerm2 – Mac OS Terminal Replacement.

If only every Mac OS X app (i.e. Quartz) would also support copy on select, middle button paste and the other X11-like features! [1] Further, I’d love to see a terminal app that disallows pasting (cmd-v) from the keyboard-controlled clipboard completely as this is potentially a very dangerous thing.

[1] Note: It’s possible to emulate X11’s behaviour to some degree using BetterTouchTool. It’s still not the same though as X11 distinguishes between the mouse-controlled buffer and the keyboard-controlled buffer and doesn’t just “paste from the clipboard”. For reference, see: