Locating unknown Raspberry Pi device in your Network

Just as a quick hint, once you have set up a new Raspberry Pi device (or probably any other device) which you don’t know, simply run the arp command to find out about your neighborhood.


arp -a

will make usage of the ARP protocol and give you some interesting information about some devices in your network.

arp -a

In my very case, I was told, the newly installed Raspberry Pi got the IPv4 address

I do not want to see this web content on Yosemite

For a couple of weeks I now this really annoying message during the start up  of my Yosemite installation.

To view this web content, you need to install the Java Runtime Environment.

If I do follow the instructions of the pop up, I usually land on the Java site.

To view this web content, you need to install the Java Runtime Environment.As I develop on a regular base, I have the latest version of Java already installed (right no it should be version 8u25). Therefore, nothing to do.

I case you thought of installing Apple’s Java version for Mac. That’s  IMHO not the way to solve the issue. You might cure the symptoms, however, you will not fix the root cause for this issue.

To get rid of the message, you need the find the root cause. In my case it was the attempt to try Facebook’s video chat some weeks ago. That was the only one installation I performed since I receive this message. Even though, I disabled the add-on in Firefeox, the message kept showing at start up.

To get finally rid of the message head straight to the terminal and enter

launchctl list

In case you wonder that launchctl does, check the manpage which says

launchctl interfaces with launchd to load, unload daemons/agents and generally control launchd. launchctl supports taking subcommands on the command line, interactively or even redirected from standard input. These commands can be stored in $HOME/.launchd.conf or /etc/launchd.conf to be read at the time launchd starts.

Anyway, you shot not get a list of off all jobs loaded into launchd. There ckeck if you can find com.facebook.videochat.{username}.updater in this list. Wondering what this is? It’s some kind of Facebook-collects-your-data thing. Honestly, I don’t want to know much more about what it does, I just want to get rid of it.

com.facebook.videochat updater

Check out

ls ~/Library/LaunchAgents/ | grep facebook

You should get something like com.facebook.videochat.{username}.plist.
Now run

launchctl unload ~/Library/LaunchAgents/com.facebook.videochat.{username}.plist

followed by

launchctl remove ~/Library/LaunchAgents/com.facebook.videochat.{username}.plist

You might want to run the following command instead

launchctl remove com.facebook.videochat.{username}.updater

You now can delete the property list file

rm ~/Library/LaunchAgents/com.facebook.videochat.{username}.plist

Now check for the FacebookUpdate application  via

ls ~/Library/Internet\ Plug-Ins/ | grep Facebook

Again, you should fine something like FacebookVideoCalling.bundle. Send it to /dev/null via

rm ~/Library/Internet\ Plug-Ins/FacebookVideoCalling.bundle

Now there still something to get rid of by calling

rm -R ~/Library/Application\ Support/Facebook/

Et voiá, your are done. The cause for the message should be gone by now.

To get rid of the JAR file itself use Spotlight to looking for FacebookVideoCalling. You should find something like FacebookVideoCalling_v1.6.jar. Use Finder then to get rid of it.

Finding FacebookVideoCalling_v1.6.jar That is, by the way, the only thing Facebook suggest to uninstall the videochat. Not only, the sort of infect you with the above updater, they also do not provide useful information for uninstalling the stuff.

The fact, Facebook’s add-on installed this nasty updater is quite annoying. Adding a job to the launchd for an Firefox add-on is quite questionable. Even more annoying that this one slipped through the cracks.

Getting Exim4 Done the Job

In my current project, moving my home server from a PC Tower running Windows Server 2003 to a more energy as well as space efficient Mac mini, I need to migrate quite a bunch of tools and scripts from Windows to Ubuntu.

Said that, hMailServer served me well for years on my local network. It was easy to install, maintain and run. However, I was now looking for some more lightweight solution for the new server.

The need can be summarized quite easily:

  • arbitrary devices and services on the local network need to be able to deliver mails via SMTP to the server
  • local services on the server need to be able to send out mails as well
  • the server needs to forward the mail to my real server
  • very basic authentication is a must
  • it need to run on my old 1.66 Ghz Mac mini

At all it’s as simple as the following diagram:

Exim4 SetupAfter digging through all the stuff such as Sendmail, Postfix and so on, I ended up with Exim4 as the perfect solution for my needs.

Basically, after installing it via

sudo apt-get install exim4

the only thing is to quickly run through the setup.

sudo dpkg-reconfigure exim4-config

It’s sort of guided and quite easy to do as long as you have some experience with networks. However, there are quite some pitfalls which are quite annoying if you are little experienced with Exim.

Network Interfaces

Assign all network interface IP addresses you want to listen for incoming mails as seen below.

Ecim4 Mail Server configurationHowever, make sure providing only IP addresses from network interfaces, which are actually connected to the network. Otherwise the daemon might fail to start.

014-12-25 10:23:46 socket bind() to port 25 for address failed: Cannot assign requested address: daemon abandoned

If the network interfaces are set up correctly, you should find the daemon listening on the network interfaces specified before:

2014-12-25 10:31:06 exim 4.82 daemon started: pid=16276, -q30m, listening for SMTP on []:25 [::1]:25 []:25

Monitoring the logs

Whenever you try to figure out what’s going wrong while connecting from any client during the setup, e.g. to check the logging information above, it might help to start tailing the log via

sudo tail -f /var/log/exim4/mainlog

The Paniclog Fail

When messing with the configuration, you might end up from time to time with the following message while starting the daemon.

ALERT: exim paniclog /var/log/exim4/paniclog has non-zero size, mail system possibly broken

Check the file, and just delete the log file after fixing the cause for the log entry.

sudo rm /var/log/exim4/paniclog

The Authentication Test

Once up and running, you might want to check the server. It might be quite convenient to check simply via Telnet by opening to your Exim server and one of the IP addresses provided before.

macbook:~ andreas$ telnet 25
 Connected to
 Escape character is '^]'.
 220 macmini ESMTP Exim 4.82 Ubuntu Thu, 25 Dec 2014 11:47:43 +0100
 250-macmini Hello macbook []
 250-SIZE 52428800
 250 HELP

Following the SMTP protocol, you can ask the server using

ehlo <someIdentifier>

The ehlo verb provides some computer-readable information about the server’s abilities, though.

Instead of Telnet you could start Exim using

exim -bh

This will bring up Exim wit a testing session.

*** SMTP testing session as if from host
**** but without any ident (RFC 1413) callback.
**** This is not for real!

>>> host in hosts_connection_nolog? no (option unset)
>>> host in host_lookup? yes (matched "*")
>>> looking up host name for
>>> IP address lookup yielded localhost
>>> gethostbyname2 looked up these IP addresses:
>>>   name=localhost address=
>>> checking addresses for localhost
>>> no IP address for localhost matched
>>> does not match any IP address for localhost
>>> host in host_reject_connection? no (option unset)
>>> host in sender_unqualified_hosts? no (option unset)
>>> host in recipient_unqualified_hosts? no (option unset)
>>> host in helo_verify_hosts? no (option unset)
>>> host in helo_try_verify_hosts? no (option unset)
>>> host in helo_accept_junk_hosts? no (option unset)
220 macmini ESMTP Exim 4.82 Ubuntu Fri, 26 Dec 2014 11:39:25 +0100

Again ask the server using ehlo.

>>> in helo_lookup_domains? no (end of list)
>>> host in pipelining_advertise_hosts? yes (matched "*")
>>> host in auth_advertise_hosts? yes (matched "*")
>>> host in tls_advertise_hosts? no (option unset)
250-macmini Hello []
250-SIZE 52428800
250 HELP

I figured this out, as one of my devices, an failed to send a status mail.

Dec 25 13:32:07 SMTP[2007]: smtp error (auth failed): 250 HELP^M
Dec 25 13:32:07 SMTP[2007]: SMTP authentication failed

The Missing Plain Auth Advertisement

So far, everything works as a charm. However, for the recent setup, I wanted to have plain authentication for most of my clients. This did cost me half a day to figure out and drove me almost mad while digging through tons of Exim docs.

First of all, activate plain authentication for the server by changing the configuration

sudo vim /etc/exim4/conf.d/auth/30_exim4-config.examples

Here you need to remove the comments from the following section

  driver = plaintext
  public_name = PLAIN
  server_condition = "${if crypteq{$auth3}{${extract{1}{:}{${lookup{$auth2}lsearch{CONFDIR/passwd}{$value}{*:*}}}}}{1}{0}}"
   server_set_id = $auth2
  server_prompts = :
  server_advertise_condition = ${if eq{$tls_in_cipher}{}{}{*}}

Finally  update the configuration

sudo update-exim4.conf

and restart Exim

sudo service exim4 restart

If you now walk through the tests above, the server will still omit the authentication advertisement.

Once that has been done, create (or edit if it already exists)the exim4.conf.localmacros file.

sudo touch /etc/exim4/exim4.conf.localmacros.
sudo vim /etc/exim4/exim4.conf.localmacro

Add the following line and restart the daemon once again.


If you now start the tests again, you will see the authentication advertisement of the server, though.

ehlo test
 >>> host in smtp_accept_max_nonmail_hosts? yes (matched "*")
 >>> test in helo_lookup_domains? no (end of list)
 >>> host in pipelining_advertise_hosts? yes (matched "*")
 >>> host in auth_advertise_hosts? yes (matched "*")
 >>> host in tls_advertise_hosts? no (option unset)
 250-macmini Hello test []
 250-SIZE 52428800
 250 HELP

Once this worked at the very end, the devices where able to send vie my Exim relay.

Test Mail from IC 3115W CameraDealing with Non System Users

When dealing with non system users, you can simply create Exim users via

sudo /usr/share/doc/exim4-base/examples/exim-adduser

That’s quite easy, when dealing with plain authentication. Keep in mind, users and passwords are stored in plain text in the /etc/exim4/passwd file.

Failed to find Host

In case you get some log entries such as

2014-12-25 12:12:31 refused relay (host) to ...; from &...; H=(...) [] (failed to find host name from IP address)

You need to add some host names for the corresponding IP addresses in /etc/hosts.


RDP from Mac to Ubuntu

I am currently in the progress of moving my entire home automation server from Windows 2003 to a Ubuntu LTS. However, connecting to the new server via SSH is quite painful. As I am using openHAB including the Eclipse-based editor, I would prefer to connect to the server from Windows and Mac via RDP.

I tried quite a while using XRDP, but almost gave up as I always had trouble, either not being able to connect or having no desktop at all.

Therefore, kudos to Mike Rehner, who came up with a step by step guide how to install and cofigure XRDP on Ubuntu.

20 minutes absolutely worth watching, especially as he comes up with two or three hints, I haven’t foundon any other tutorial so far such as

  • you are going to need a 2D desktop such as MATE Desktop Environment
  • you need to connect several times using the RDP as the first or second attempt might fail
  • how to change the XRDP settings to be able to connect to previous session

The proof, I was able to connect to the Ubuntu via my Mac, though:

XRDP Mac OS X Ubuntu


Removing Failed Thecus Moule Installations

For whatever reason it might happen, a module installation on a Thecus NAS Server won’t succeed. In such a case even removing the module might fail. In my case, I had to troubleshoot my Thecus N4200PRO with the latest 32-bit firmware 5.03.01.


Symptoms included a module which did not start at all with the message

Module[Mail Server]: Enable Fail.

and uninstalling the module stopping with the message

Module[Mail Server]: Uninstall Fail.

Even worse, re-installing the module was not possible as the server assumed the module already was installed and uploading the module manually failed as well.

To solve this kind of Mexican standoff you probably need to dig somewhat into the Thecus, though.


First of all make sure the SSH module (HiSSH) is installed and enabled.

HiSSH Module

You need to log in via the user root using the same password provided for your admin user, though.

macbookpro:~ andreas$ ssh -l root
root@'s password:

Cleaning Up

Depending what failed during your installation, only some of the following steps might be necessary to clean up the module.

Files related to the module might be found in the following three directories and need to be removed.


In case anything related to your module can be found there (such as Mailserver in my very case), you can remove them with one of the following commands.

rm -rf "/raid/data/module/cfg/module.rc/Mailserver.rc"
rm -rf "/raid/data/module/Mailserver"
rm -f "/img/htdocs/module/Mailserver"

Once all related files have been removed, you now head for the database and clean up the two affected tables. As sqlite won’t give any feedback about succeeded operations, makew sure entries are there before cleaning up and are gone afterwards.

root@ /opt/bin/sqlite /raid/data/module/cfg/module.db "SELECT * FROM module WHERE name = 'Mailserver'"
Mailserver|2.00.02|Mail Server|No||md_mailServer.png|User|www/index.htm|User

root@ /opt/bin/sqlite /raid/data/module/cfg/module.db "DELETE FROM module WHERE name = 'Mailserver'"

root@ /opt/bin/sqlite /raid/data/module/cfg/module.db "SELECT * FROM module WHERE name = 'Mailserver'"

If the deletion works well, you should experience some delay after the delete statement was executed.

root@ /opt/bin/sqlite /raid/data/module/cfg/module.db "SELECT * FROM mod WHERE module = 'Mailserver'"
Mailserver|1|Name|Mail Server
Mailserver|1|Description|Mail Server
Mailserver|1|Authors|Davide Libenzi
Mailserver|1|Thanks|XMail by Davide Libenzi

root@ /opt/bin/sqlite /raid/data/module/cfg/module.db "DELETE FROM mod WHERE module = 'Mailserver'"

root@ /opt/bin/sqlite /raid/data/module/cfg/module.db "SELECT * FROM mod WHERE module = 'Mailserver'"

Once both tables are cleaned, you might want to reboot the NAS.


The Mail Server module failed for me, as I did not install the MySQL Module before. Unfortunately, the installation did break somewhere in the middle leaving some tries in the database for me without the files being copied to the corresponding directories. Therefore, the uninstall.sh script was missing to get rid of the bricked module. As the Thecus user interface won’t let you re-install the module nor uninstalled it due to the missing script, there is only litte you can do without knowing about the internals of the server. With the few steps provided above, unblocking most of the modules should work as long as you are able to install the SSH module on you NAS.

Ubuntu: Setting up Oracle JDK

Since Oracle’s Java SDK is not part of Ubuntu, there are some steps required to get Java set up on a Ubuntu system. Especially running a 64-bit version of Ubuntu requires one tiny additional step driving you crazy in case do not speak Ubuntu fluently.

There are quite some scripts and tutorials out there how to get Oracle’s Java working on a Ubuntu system, however, there are only a few steps necessary to do so:

Pick the bits from Oracle’s download site and extract the archive using tar. In my case we use the 32-bit version of the JDK

tar -xvf ~/Downloads/jdk-7u15-linux-i586.tar.g

Create a folder and move all the stuff over there

sudo mkdir -p /usr/lib/jvm/jdk1.7.0 
sudo mv jdk1.7.0_15/* /usr/lib/jvm/jdk1.7.0/

Now set up the symbolic links for java, javac and javaws.

sudo update-alternatives --install "/usr/bin/java" "java" "/usr/lib/jvm/jdk1.7.0/bin/java" 1
sudo update-alternatives --install "/usr/bin/javac" "javac" "/usr/lib/jvm/jdk1.7.0/bin/javac" 1
sudo update-alternatives --install "/usr/bin/javaws" "javaws" "/usr/lib/jvm/jdk1.7.0/bin/javaws" 1

Now, create a Bourne script to set the JAVA_HOME variable and update the PATH variable. In case you haven’t used Vim yet, get it using

sudo apt-get install vim

and then create the file

sudo vim /etc/profile.d/java7.sh

edit the file file and add the following export statements

export JAVA_HOME=/usr/lib/jvm/jdk1.7.0
export PATH=$PATH:$JAVA_HOME/bin

Finally execute the script

source /etc/profile

and try to call java. If you run a freshly set up Ubuntu such as mine, you probably will end up the system telling you

bash: /usr/bin/java: No such file or directory

What happened? Actually, we installed a 32-bit version of the JDK, however as mentioned at the beginning running a 64-bit version of Ubuntu and therefore we come back to this very tiny bit missing. One additional package is required to run the 32-bit version: libc6-i386.

“This package includes shared versions of the standard C library and the standard math library, as well as many others. This is the 32bit version of the library, meant for AMD64 systems.”

Said that, get it

sudo apt-get install libc6-i386

and try to run java one more time. It should work now fine.

Got Root #3

In this article I provide the final steps how to virtualize a Windows Server 2008 installation.

Install Windows Server 2008

You probably run into the same problem that Windows Server 2008 won’t be able to recognize the virtual hard disk you have planned to installed it on. Get the corresponding SCSI drivers as floppy image from the VMware site. Select the image and connect the drive.

Mounted SCSI Drivers

Now say ‘Browse‘ and choose drive ‘A:‘ – don’t forget: After selecting the .flp image you also have to connect the drive. Otherwise Windows cannot read the device.

VMware SCSI Drivers

Click on ‘Next‘ and after a few seconds the hard disk will be found. The currently available drivers for Windows Server 2003 seem to work fine also for Windows Server 2008.

Virtual HDD for Windows Server 2008

Installing the VMware Tools might be a good idea. You can find the image at /usr/lib/vmware/isoimages/windows.iso or just install them from the VMware management console’s menu. While the image is mounted go to ‘Device Manager‘ and install the drivers for the network adapter which probably does not work yet.

Installed Network Drivers

Got Root #2

In a previous post, I told about he first steps in virtualizing a Windows Server 2008. In this article I describe how to proceed after, the request for my own RIPE subnet was approved. Now I can concentrate on the next point: Installing VMware. Since I want to set up this machine for visualization, I have to perform a few steps first. That way, this post will be mostly about my fight with Debian Linux which is the host system.

After logging in, I just realize that updating the package database might be not the worst idea. Consequently, I do so and install some Norton Commander like tool for real men

apt-get update
apt-get install mc

This actually makes things much easier.

Now, I have to activate IP forwarding in /etc/sysctl.conf by the adding


and bringing the additional IP on the host system by adding

up ip add dev eth0

to /etc/network/interfaces. Additionally, I have to add some host-route (by using my gateway so my new subnet is reachable by adding


to eth0 in /etc/network/interfaces. Installing iproute by a

apt-get install iproute 

restarting the interface by calling

/etc/init.d/network restart

finally makes my IP ping-able. Quite a fight so far if you don’t do this on a regular base. Additionally I installed the powersave package and reconfigured several settings to increase the performance in /etc/powersave.

I just got the tip to put my virtual machines to the separate disc. Since I have one spare 400GB disc. I have to create some partition and to format it.

cfdisk /dev/sdb mkfs -t ext3 /dev/sdb1

Let’s create some directory for the virtual machines and mount the disc

mkdir VMs
mount -t ext3 /dev/sdb1 /Vms

Now some final tweak at /etc/fstab by adding

/dev/sdb1 /VMs et3 defaults 0 0 

and I am done.

Finally I start installing the VM. I was pointed to some German How-To written by Till Brehm which is includes quite detailed instructions.

Some prerequisites are required before I start. I do the required 220 MB update by

apt-get install linux-headers-`uname -r` libx11-6 libx11-dev x-window-system-core x-window-system xspecs libxtst6 psmisc build-essential

VMware can be downloaded from http://www.vmware.com/download/server/. I skip the management console since I will use it on my Windows workstation and focus only on the server and management interface binaries using:

wget http://download3.vmware.com/... tar xvz VMware-server-*.tar.gz cd vmware-server-distrib ./vmware-install.pl

Now, I simply accept the defaults for the following installation. only at one point I had to tell the script that my virtual machines will be located at /VMs. No I have to continuing with the management interface

tar xvfz VMware-mui-*.tar.gz
cd vmware-mui-distrib

The Web-based management interface seems to work perfectly after installing.

VMware Management Interface

After installing the management console on Windows I run into some trouble. During compilation of the corresponding modules, the VMware script was not able to start the inetd service. Therefore, I was not able to connect to the VMware server. After restarting the service manually it worked perfectly and I set up my virtual machine.

VMware Management Console

Now, I have to copy the installation files for the Windows Server 2008.


Got Root #1

Today, I finally got my root server. this article will be the first one in a series of articles showing how to virtualize a Windows Server 2008 on a remote system.

Got Root

My very first action was to request a new RIPE subnet. Unlike in your private LAN, you cannot simply assign randomly some IP to any machine. Nothing else I can do until the subnet is assigned.