Install Wireshark:

yum install wireshark

Run a capture:

tethereal -i eth1 -w ~/mycapture.pcap

This command will run Wireshark/Ethereal, capture on the eth1 interface and output the data to /yourhomedir/mycapture.pcap

Why would you want to do this? If you want to capture packets from a headless or remote Linux PC and analyse the data elsewhere.

Right now I’m at home, but I have a headless CentOS box at work that’s running ntop from a mirrored port, in order to look at network traffic flowing over the router. To increase the capability of the CentOS box, I want to use it to capture packets using Wireshark, then download the .pcap file over WinSCP and look at the data on my laptop using Wireshark for Windows.

Surely it can’t be that hard? I’m thinking possibly something like a tiny Linux distribution embedded into the TV, something akin to the “Instant Play” feature on many laptops.

AllowUsers joeuser

To add multiple entries, either separate users with a space, or write an entirely new line:

AllowUsers joeuser philwiffen

AllowUsers joeuser
AllowUsers philwiffen

To get OpenOffice to Save in Microsoft Word .doc format by default, follow these steps:

• Tools > Options
• Load/Save > General
• In the bottom right of the window, look for “Always save as” and pick your poison

I know that saving in a proprietary format over an open standard is bad practice, but sometimes in Business you need to maintain interoperability with the de facto standard; in this case: Microsoft Word.

• Go to the Lightning download page
• Right click on the download link and Save As… (If you don’t, Firefox might try to install the add-on itself.)
• Open up Thunderbird and click on Tools > Add-ons
• Install the Lightning file you just downloaded
• Once you’re done, restart Thunderbird, and start using your new Calendar feature!
• If you need Holiday calendars, you can get them here

To combat this, I set up a regular log rotation in Plesk like so:

• Log in to Plesk.
• Domains > yourdomain.com > Log Manager > Log Rotation
• Choose the log rotation condition.

I choose monthly, but if you’re rapidly running out of disk space you might want to set a shorter time span, or set a low size limit. Don’t forget to enable compression to save on disk space!

sudo apt-get install smartmontools

Why would you want SmartMonTools?

The smartmontools package contains two utility programs (smartctl and smartd) to control and monitor storage systems using the Self-Monitoring, Analysis and Reporting Technology System (S.M.A.R.T.) built into most modern ATA and SCSI hard disks. It is derived from the smartsuite package, and includes support for ATA/ATAPI-5 disks. It should run on any modern Linux system.

Ubuntu smartmontools page

Very handy; especially as the OS drive just died in the RAID5 box I’m now taking extra precautions!

Make sure we have the latest updates

Check for updates:

sudo apt-get update

Install any updates:

sudo apt-get upgrade

Now prepare to upgrade to 7.04

Install the latest upgrade manager:

sudo apt-get install update-manager-core

Run the upgrade tool for servers:

sudo do-release-upgrade

And everything went smoothly. The only issue I had, was that I had to install inetd again to get SWAT working (sudo apt-get install netkit-inetd). Everytime I use Ubuntu I fall more and more in love with it

1. Open up a Terminal: Applications > Accessories > Terminal
2. sudo apt-get install kismet
3. sudo gedit /etc/kismet/kismet.conf
4. Change
source=none,none,addme
   to
   source=ipw2200,eth1,wifi
   • If you don’t know your relevant network driver, view the Kismet Readme and scroll down to the section “12. Capture Sources”. My driver is ipw2200.
   • If you don’t know your interface name, use iwconfig to find your wireless interface (mine is eth1). [screenshot]
5. Save the file
6. sudo kismet [screenshot]

Any questions? Feel free to leave me a comment below

Finding files on our previous 300GB PowerVault was nothing short of a nightmare and, with such a vast amount of data on the new system, we have to ensure that information won’t get ‘lost’ as easily. Obviously proper structuring of directories through a bit of Information Architecture will help, but what we really need is a search facility.

As a small company with a limited budget, the search facility has to be affordable. In addition, it needs to be easily accessible to everyone in the network, preferably without installing extra applications onto client systems…

After a bit of digging around, and discounting the costly Google Appliance and Google Desktop Enterprise (Unfortunately, we don’t run an Active Directory network), I stumbled across IBM’s OmniFind Yahoo! Edition. It’s a free edition of their OmniFind software – which retails for thousands of dollars – and installs on both Linux (with a GUI) and Windows. Key features for us are that:

1. It’s free.
2. It’s simple to setup.
3. It provides a search interface to users through a browser. (http://hostname:8080/)

As my Ubuntu system is purely command line, OmniFind wouldn’t install, so I’ll be reusing the old 300GB PowerVault that this 2.7TB Linux system will replace. I’m playing with it right now and it’s incredibly easy to use. Setting up indexing is a doddle and there’s plenty of customisation options for the web interface that users will see when searching, including:

• Logo replacement, allowing you to re-inforce corporate branding.
• Featured links, drawing attention to essential information.
• Ranking modification

Once it’s indexed all of our data, I’ll play with it, see how it performs, and update the blog

sudo apt-get install mdadm
sudo mdadm --create /dev/md0 --raid-devices=5 /dev/sd[abcde]1 --level=raid5
sudo mke2fs -j /dev/md0
sudo mount /dev/md0 /mnt/raid

To explain a little:

The first command installs mdadm.

The second command creates the raid array /dev/md0, then sets how many disks – and their respective locations – there’ll be in the array. In my case, we have 5 750GB drives, which are /dev/sda through to /dev/sde. The 1 is the partition identifier. Level sets the raid level, which in this case is raid5.

The third command ‘sudo mke2fs -j /dev/md0 ‘ makes an ext3 filesystem on the array.

And finally ‘sudo mount /dev/md0 /mnt/raid‘ mounts the array to /mnt/raid (you can mount it wherever you like)

Note 1: Make sure you have mdadm installed. If you don’t: sudo apt-get install mdadm

Note 2: If you’re not using Ubuntu, su to root and run the commands without ‘sudo’

Note 3: If you get an error stating ‘mdadm: error opening /dev/md0: No such file or directory’, you need to bypass udev and use this command instead: sudo mdadm --create /dev/md0 --raid-devices=5 /dev/sd[abcde]1 --level=raid5 --auto=yes

Note 4: To view the status of your array: sudo mdadm --detail /dev/md0

Note 5: If you need to view a list of your hard drives, try these commands: ls -l /dev/sd* or ls -l /dev/hd*

I am certainly no Linux expert. Corrections, and suggestions on how to improve this method are encouraged

Update: There’s a very thorough guide here, but it seems to cover some GUI elements – which wasn’t an option for me.

I thought I’d found a solution by changing the Bash language but it broke some stuff (including yum) so I went back to the default and put up with it. By chance, whilst browsing around atomicrocketturtle.com, I found Scott had fixed the same problem far more elegantly:

Here a quick step-by-step guide for FC4, on the 64-bit systems:

1. Login as root (or su)
2. Backup your yum.conf file: cp /etc/yum.conf /etc/yum.conf.YYYY-MM-DD
3. Edit your /etc/yum.conf file
4. Comment out the entries in your yum.conf which feature ‘update.onlinehome-server.info’. That server doesn’t work right now, and by commenting them out, yum will resort to the defaults in /etc/yum.repo.d
5. Save yum.conf
6. Run: yum install system-config-language
7. You’ll be asked to confirm. Now, let it install…
8. To change the language, run this from the command line: system-config-language
9. Scroll up and choose English (British) (or whatever language you want).
10. Hit the Tab key to switch to “OK”
11. Hit return.
12. Ta-da, English language feedback

For reference, your yum.conf should look something like this: yum.conf.txt

I needed to do this to allow Plesk to login to our old servers during the big migration, as it can’t login as admin, then su to root

SpamAssassin uses SPF to detect header and email-source forgery – very important in determining if e-mail is legitimate or not.

To install Mail::SPF::Query, run these commands as root:

perl -MCPAN -e shell
install Mail::SPF::Query

If you haven’t yet added SPF records to your DNS, you can find out more at the Sender Policy Framework site

SpamAssassin uses SPF to detect header and email-source forgery – very important in determining if e-mail is legitimate or not.

To install Mail::SPF::Query, run these commands as root:

perl -MCPAN -e shell
install Mail::SPF::Query

If you haven’t yet added SPF records to your DNS, you can find out more at the Sender Policy Framework site

You can sign the key by typing “gpg --sign-key user-id” at the command prompt.

Footnote: I came across this whilst migrating our e-commerce system to a new server. The system uses GnuPG to encrypt the order/credit card information and then emails it to our sales team. I’m making sure I document the process fully, so that I don’t have to spend so much time figuring this stuff out again!

export LANG=en

For some bizarre reason, our new dedicated server from 1and1 defaults to German feedback, which is really handy when you’re trying to work on the shell!

Update – 2007-02-27: If you have a 1and1 server stuck in German, this solution above doesn’t work properly (it breaks some stuff). I’ve written up a much more elegant solution which does actually work (thanks to Scott from ART).

RedirectMatch permanent .* http://yoursite.com/migration.html

RedirectMatch temp .* http://yoursite.com/migration.html

Make sure you point to a different domain than the one you’re migrating!