Monday 29 November 2010

Demise of the DELL

Recently, I wrote about synchronizing Windows mobile PIM data with Thunderbird on my Ubuntu distro. I have a couple of PDAs running Windows mobile: a DELL Axim X50 (running WinMob 2003) and an HP iPAQ hx2790 (running WinMob 5.0). Since publishing my tutorial, I have been happily synchronizing both devices successfully over my home network.

However, my recent attempts to improve my understanding of small networks have persuaded me to improve my wireless access security from WEP to WPA and this simple change of security encryption played havoc with my PDAs: after changing to the more secure WPA protocol, neither could connect to the network. A little research suggested that this is a well-known problem and HP has already issued a fix for my iPAQ: however, installing it still didn't allow my device to connect but, following some chatter on various forums, I suspected that using Odyssey Client (pdf) might provide the solution. Fortunately, although Odyssey isn't installed by default on the iPAQ, HP ships a licenced copy on the companion CD (at least, it did with my hx2790!) and installing it is simple using Activesync or Mobile Device Center (and a Windows machine, obviously!). Once installed, configuring the client was straightforward and my iPAQ rejoined my network as a wireless node.

Sadly, the news for my X50 is not so good. DELL did ship the X50 with a pre-installed version of Odyssey, but even with this utility running, my PDA can't connect to my wireless access point even though it has no trouble detecting the network. Even a hard reset hasn't had the desired effect and I suspect that the DELL will shortly be consigned to the drawer where legacy devices go to die.

Friday 26 November 2010

Networking For the Rest of Us


Network Know-How: An Essential Guide for the Accidental Admin
John Ross
No Starch Press
ISBN: 978-1-59327-191-6

It is unlikely that those with extensive theoretical and practical experience of designing, building and maintaining small computer networks will find much of interest in John Ross' book. However, if like me you are the archetypal "accidental admin", this may just be the most useful computer book that you ever buy!

In Network Know-how, Ross introduces the novice network manager to the basic concepts of networking and provides important insights into why things work (or sometimes don’t work) in small network environments. He offers practical advice on LAN design as well as equipment and infrastructure installation, giving concise instructions on how to setup and operate a range of servers, clients, and peripherals. All this Ross achieves without resorting to unnecessary jargon or gross over-simplification: in short, it is networking for the rest of us!

Given the extensive range of hardware and software available, the book does tend to be understandably vague regarding hardware and, in places, a little Windows-centric. Nevertheless, Ross has been careful to provide pointers for Mac and Linux users even if it is not as comprehensive as one would have liked and, because he explains the principles of networking so well, these signposts are more than sufficient to cope with all but the most specialised kit. Reading this book has resulted in significantly improved security in my own network and the ability to share files and services across multiple operating platforms (Windows, Windows Mobile, & Linux) and devices.

Overall, this book is a thoroughly recommended tract on networking for non-specialists. As with all books of the genre, this one is over-priced. However, don't let this fool you into believing that it is not value for money: if you want a secure and reliable network over which you can share data and resources, this is an excellent introduction.

Thursday 25 November 2010

If at First You Don't Succeed...

My ongoing battle with my NAS and netbios names prompted me to wonder whether I could share files between my Ubuntu machine and Windows Vista. In theory, a public share on the network from Linux should be a simple matter but, even sharing a directory as root via Samba, met with no success.

However, one thing that I have learned from my fight with my network is that trial and error only gets you so far: at some point you have to understand how things work in order to get things done. Clearly, my accumulated networking knowledge needed to be put on a more secure noetic footing if I was ever going to get my disparate operating systems and network nodes talking to one another.

In an effort to combine my practical experience with some meaningful intellectual understanding, I turned to John Ross' excellent book, Network Know-how: an essential guide for the accidental admin. It was here that I discovered how subnets are identified which, in turn, triggered my understanding of why Samba wasn't doing what I expected.

The /etc/samba/smb.conf file, specifies which hosts (servers) can connect to your machine in order to share directories and files. These are called the allowed hosts and you have to tell Samba what they are by changing the configuration file.

Open the Smb.conf file:

sudo gedit /etc/samba/smb.conf

Enter your password when prompted and the smb.conf file will open in a plain text editor. Look for the line that identifies the allowed hosts (mine is line 7) and add your LAN subnet address. For instance, if your LAN IP address is 192.168.1.1, then your LAN subnet is 192.168.1 and that's all you need to add.

Save and close the file.

Restart Samba:

sudo /etc/init.d/samba restart


Hey Presto! Suddenly all of my shares appeared in Nautilus and I could see my shared directories in File Explorer from my Windows Vista box!

But that's not the best news...

After amending my Samba configuration, I can now use netbios names rather than IP addresses meaning, in theory at least, that I can return to dynamic IP addresses and no longer worry about moving my network around!

How cool is that?

Thursday 11 November 2010

Follow the KISS Principle

Sometimes I'm so busy trying to be clever I don't bother to try the simple solutions!

You may recall that earlier this week I suggested that bookmarking my NAS device in Nautilus rather than mounting it as a permanent share meant that, among other things, I couldn't view thumbnails in the file browser. This is of course just wrong!As always, Linux makes viewing thumbnails on remote drives simple but doesn't make it the default behaviour.

To change your settings:
  1. Open Nautilus from the Places menu on your Panel
  2. Click on Edit and then select Preferences
  3. Select the Preview tab and, under the Show Thumbnails: option (in the Other Previewable Files section), select "Always"
As is often the case, the simple solution is often the best choice!

Tuesday 9 November 2010

The Battle Continues!

After thinking that I had finally resolved my problems with mounting a Windows NAS to my Ubuntu box, I've noticed that my system takes upwards of two minutes to shutdown. It wasn't a huge problem as, whatever was hanging at shutdown eventually timed-out and the box closed down successfully.

However, things like this irritate me and I just had to find out what was causing the problem. Running the usual logs (/var/log/dmesg & /var/log/messages) suggested that the problem was some sort of segfault with Python: that didn't make much sense to me as I hadn't done anything to cause Python to hang.

So, working on the assumption that the last thing I did caused the problem, my attention returned to my ongoing battle with my network attached storage device. A simple test to see if this was the problem revealed that, for some as yet undetermined reason, the NAS wasn't being unmounted properly at shutdown causing some kind of network interface error.

I used the CLI to unmount the NAS

sudo umount /media/device_name

Where device_name is the name of the NAS (in my case, mybook). Thereafter, shutting Ubuntu down took seconds rather than minutes indicating that I had found the problem.

After struggling for a week to get Ubuntu to mount the network share, I didn't really want to undo everything, but I did want to stop the automatic mount at bootup. This is easy: just comment out the device line in the fstab file.

sudo gedit /etc/fstab

Add a # (hash) to the relevant device and grub will ignore the line at boot. My file looks like this:

# /etc/fstab: static file system information.
#
# Use 'blkid -o value -s UUID' to print the universally unique identifier
# for a device; this may be used with UUID= as a more robust way to name
# devices that works even if disks are added and removed. See fstab(5).
#
#
proc /proc proc defaults 0 0
# / was on /dev/sda1 during installation
UUID=d5837259-b437-46a8-a10c-3d962bf58e41 / ext4 errors=remount-ro 0 1
# swap was on /dev/sda5 during installation
UUID=1b210c31-3575-4179-8fbd-c72984f8c8bb none swap sw 0 0
/dev/scd0 /media/cdrom0 udf,iso9660 user,noauto,exec,utf8 0 0
/dev/fd0 /media/floppy0 auto rw,user,noauto,exec,utf8 0 0
#//MYBOOKWORLD/id19748494 /media/mybook cifs credentials=/home/jogga/.smbcredentials 0 0


I can still reach the device using Nautilus and the ip address but I can't use the device name (Netbios name) or the ip address to mount the device.

Monday 8 November 2010

Revisiting Rhythm

Following my post about repairing my Rhythmbox library, a friend of mine over at Delliberate suggested that a better way of achieving my goal was to mount my network drive as a permanent Windows share on my Ubuntu box.

I've struggled with this for over a week, trying to get Ubuntu and Samba to play nice with Netbios names (clearly, using the IP address to establish the mount defeats the object!) but eventually had to acknowledge that the problem was better than I! Nautilus connects to my network drive using the ip address without any difficulty, all that is required is to type the ip address of the drive followed by the share name into the location dialog box in Nautilus using:

smb://###.###.###.###/share_name

Where ###.###.###.### is the ip address for the drive and share_name is the name of the directory (or folder) that you want to reach. Instructions for creating a permanent mount point can be found at the Ubuntu Wiki (here) and, if you can't get Ubuntu to resolve Netbios names, you can substitute the ip address for the server name.

However, today I found a workaround that, whilst it doesn't completely solve the problem of Netbios resolution, does provide a partial solution. You can add the Netbios name to the /etc/hosts file and Nautilus will use this to resolve the ip address to the device name. Open the /etc/hosts/ file:

sudo gedit /etc/hosts

and input your password when prompted. Add the ip address and the Netbios name as follows:

###.###.###.### Netbios_Name

My file output looks like this:

127.0.0.1 localhost
127.0.1.1 jogga-desktop
192.168.1.10 MYBOOKWORLD
# The following lines are desirable for IPv6 capable hosts
::1 localhost ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
ff02::3 ip6-allhosts


Line 3 is the one of interest! If I've understood how this works properly, Nautilus uses the etc/samba/smb.conf file to resolve Netbios names (in a specific order): the smb.conf file specifically lists the host as a reference source. Now I can use the Netbios name rather than the ip address which is more intuitive when searching and browsing in Nautilus. In my case, I type:

smb://MYBOOKWORLD/Share_Name

I also had to change the /etc/fstab file in order to make the permanent mount resolve the MYBOOKWORLD name as per the instructions at the Ubuntu Wiki (linked above).

Of course, if the ip address changes, the workaround stops working! However, it's a simple matter to amend the /etc/hosts file to reflect the new ip address and all bookmarks that use the Netbios name should be restored to rude health!

There are some tangible benefits of mounting a network share at boot, not least, pictures and video render in Nautilus (as opposed to icons), making file identification much easier, so it's been worth the pain.

Sunday 7 November 2010

Wallpaper Fetish

By now you may have realized that I like playing around with the decorations on my Ubuntu box! However, if you take lots of photographs and want a quick and convenient way of setting one as your wallpaper, download and install nautilus-wallpaper from the repository (or use Synaptic)

sudo apt-get install nautilus-wallpaper

Enter your password at the prompt.

After rebooting your PC, you can right-click any picture in your directory and select the (new) Set as Wallpaper... option.

Monday 1 November 2010

Redecorating

Changing wallpaper and themes is a great way of revitalizing the Ubuntu experience, but have you ever noticed how a fabulous looking picture can drown out text and icons on your panels and desktop? Sometimes, the effect is so bad as to render even the best pictures unusable as a wallpaper!

However, there is a simple way to adjust some of the colours and settings of these essential elements without having to write clever scripts (or copy them from the Internet ;)): install Gnome Colour Chooser from the Ubuntu Software Centre.
  1. From the Applications menu, select the Ubuntu Software Centre
  2. Type Gnome Colour Chooser into the search box
  3. Install the application
It's that easy!

Once installed, you'll find the application shortcut in the System → Preferences Menu and just click the icon to open the program.



One of the real benefits is being able to change the properties of the font (colour, size, and style), allowing you to use dark backgrounds without loosing sight of your menus, but there is a host of options to play with and you can have hours of fun designing (should that be, redesigning?) your theme.

Enjoy!