WireShark is an invaluable tool in recording and reviewing network traffic, it was previously known as Ethereal and is available for a variety of platforms.
Installation can sometimes be hard to remember as use by non-superusers requires additional configuration in Linux.
- Add the repository and install:
sudo add-apt-repository ppa:wireshark-dev/stable
sudo apt-get update
sudo apt-get install wireshark
- During installation, the following will appear, chose "Yes" for most instances.
Should non-super users be able to capture packets - Yes / No?
- If you need to change the value you selected, you can always re-run the following:
- Add the user to the
wireshark group so that they can capture traffic:
add user to group:
sudo usermod -a -G wireshark username
- If you need additional information, you can always RTFM:
sudo vi /usr/share/doc/wireshark-common/README.Debian.
Ubuntu updates occasionally fail due to IPv6 update servers not being reachable. While I prefer to keep IPV6 activated, this approach will allow you to disable it for updates, simply reverse the steps to re-enable afterwards!
- Update the configuration file…
sudo vi /etc/sysctl.conf
# IPv6 disabled
net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1
net.ipv6.conf.lo.disable_ipv6 = 1
Then, you must enable the change…
sudo sysctl -p
- To verify…
Splunk is a popular enterprise level tool for log collection, analysis and management. While you can obtain an enterprise license, most functions are available in the free community edition.
Setup is very easy:
- Download and move the .tar.gz file to the appropriate server (i386 vs. amd64)
sudo dpkg -i splunk*.deb
- Start the server:
sudo /opt/splunk/bin/splunk start
The first time you run after installation or update you will have to accept terms.
Access the admin screen:
Go to Settings/Forwarding * Receiving
– add new (port 9997)
- Open firewall port (if enabled):
sudo ufw allow 8000
Now to start as a service…
sudo /opt/splunk/bin/splunk enable boot-start
I’ve done a LOT of web and software development in my career, one of the biggest problems I’v e had is doing proper testing on various platforms. VirtualBox can be run on most platforms, and allows for you to virtualize various operating systems. Apple’s OS X can be problematic to install, here’s some functioning instructions and settings that I’ve successfully used for my virtual Hackintosh test environment.
WARNING: As this uses an image of the software, it is advisable to also have a valid licenced copy as to use this without a licence would be “stealing”.
NOTE: this is a version of Snow Leopard, unfortunately you will NOT be able to update or add “fixes” to this test copy as it will usually break. I recommend making a copy of the VM if you wish to try!
My VirtualBox settings:
Mac OS X
Mac OS X Snow Leopard (64-bit)
- English, continue
- Utilities… disk Utilities… Select drive, Erase, name, erase… close
- Select disk… continue
- Customize (see instructions for: updates, kernels & bootloaders)
NOTE: i only did 10.6.1 (an earlier 10.6.2 failed)
- Resolution fix – (I could not save file, but here are the instructions…
Finder > OSX Drive (On desktop) > Extras > com.apple.Boot.plist (open with TextEdit – use the field to find)
DomainKeys (originally from Yahoo!) and Cisco, and later as an industry collaboration, is a means for and organization to claim responsibility for sending a message, in a way that can be validated by a recipient. As a result, emails are “signed” by the outgoing SMTP server and can be verified against a DNS record. Depending upon the receiver, unsigned emails MAY be treated or marked as SPAM as they could be forgeries.
The below instructions assume Ubuntu (Debian) and Postfix, but could likely be modified for other platforms.
I’ve found New Relic to be a great free addition to my suite of tools for server monitoring and alerting as I shifted to a DevOps support environment.
Installation is very fast an simple once you’ve created a free accound. Paid options are available and allow for more features.
You will need to record/save YOUR_LICENSE_KEY from your account for step 5 below.
sudo sh -c 'echo deb http://apt.newrelic.com/debian/ newrelic non-free > /etc/apt/sources.list.d/newrelic.list'
wget -O- https://download.newrelic.com/548C16BF.gpg | sudo apt-key add -
sudo apt-get update
sudo apt-get install newrelic-sysmond
sudo nrsysmond-config --set license_key=YOUR_LICENSE_KEY
sudo /etc/init.d/newrelic-sysmond start
You are done! Within a few minutes you should start seeing data on your consoles at the New Relic website.
Shortly updating to Ubuntu Trusty (14.04), I noticed the following warning on my console during updates. I finally got around to looking into it deeper and found that many users have seen this too.
Warning: Setting GRUB_TIMEOUT to a non-zero value when GRUB_HIDDEN_TIMEOUT is set is no longer supported.
If you edit the ‘grub’ file, you can comment out the GRUB_HIDDEN_TIMEOUT line by adding a hash in front of it.
sudo vi /etc/default/grub
Verify that the error is fixed by executing the following:
If you are interested, you can also go and look at the updated ‘grub’ file at
NOTE: I’d also seen that the following command could be used, but it was of no use in my testing.
The Canonical/Ubuntu Landscape service has been around for as long as I can remember using Ubuntu. A free trial period is enabled (re-enabled?) when a new installation occurs, that allows for a server administrator to see performance metrics and uptime information for any hardware that is running the client. After the trial ends, it is still a quick means of visually observing some key statistics in the terminal MOTD at login. I’d also noticed that it was still doing DNS lookups to “
landscape.canonical.com” on a regular basis, and while I did not look for it, I assume that some information was still being collected and reported upon.
As there are MANY other ways to get server performance information, I decided that it was time to be rid of landscape itself.
Removal is easy, as only one line is required… I chose to “purge” all references, though you can “remove” if you feel inclined to leave any configuration for possible later re-installation.
sudo apt-get purge landscape-client landscape-client-ui landscape-client-ui-install landscape-common
Subversion is a commonly used central version control system for software development. There are currently still a large number of organizations that rely upon it, many have since moved on to Git.
sudo apt-get install apache2 apache2-utils
sudo apt-get install subversion subversion-tools libapache2-svn
sudo mkdir /home/svn
svnadmin create /home/svn/test
Create a group for subversion users:
sudo groupadd subversion
sudo adduser USERNAME
Add a user to the group:
sudo useradd -G USERNAME subversion
sudo chown -R www-data:subversion /home/svn/test
sudo chmod -R g+rws /home/svn/test
sudo a2enmod dav_svn
To create/clobber a new file for the first user:
sudo htpasswd -c /etc/apache2/.htpasswd YOURUSER
To add additional users:
sudo htpasswd /etc/apache2/.htpasswd YOURUSER
(repeat for new users without the -c as that creates/clobbers the file)
sudo vi /etc/apache2/sites-available/000-default.conf
Then add to the bottom:
(NOTE1: the LimitExcept can be enabled to allow anonymous access):
(NOTE2: the LimitXMLRequestBody can be uncomment to allow large commits)
AuthName "Subversion Repository"
# AuthUserFile /etc/svn-auth
#<LimitExcept GET PROPFIND OPTIONS REPORT>
sudo service apache2 reload
sudo service apache2 restart
NOTE: At this point you should be able to browse and do a remote checkout of the code from another machine….
svn co http://YOUR-IP-OR-HOSTNAME/svn/test --username YOURUSER --password YOURPASS
sudo vi /etc/init/svnserve.conf
Add the following:
# svnserve - Subversion server
description "Subversion server"
start on (local-filesystems and net-device-up IFACE=lo and started udev-finish)
stop on runlevel 
respawn limit 2 3600
exec /usr/bin/svnserve --foreground --daemon --config-file /home/svn/repos/conf/svnserve.conf --root /home/svn/repos/
sudo initctl start svnserve
Back on the client side…
Create a new folder inside your user folder:
Check out the project into this folder:
svn checkout http://YOUR-IP-OR-HOSTNAME/svn/test
Let us just add a new HTML index file to the folder:
Add it to version control:
svn add index.html
Commit the new file:
svn commit -m "commit message"
That should cover most cases for you…
I’ve recently resurrected some old java code that I’d written back when I primarily used Windows instead of Ubuntu for development. In some of that legacy code, the temporary file paths were hardcoded, to make things more modern and portable, The following line is recommended to get the Operating System values regardless of where it is installed and ran. The file separator “slash” can also be determined in this manner.
private static final String TMPDIR = System.getProperty("java.io.tmpdir") + java.io.File.separatorChar;