Archive for the 'Linux' Category
WDS Bridging Experiences
At the moment, our best solution for network coverage to multiple buildings is wireless. I have been planning out various solutions to improve our system (fiber optics, dslam, or a better wireless setup) but wanted to share what we have now and how well it has worked in this particular area of our property.
The image above shows the main buildings that are being linked. The main router sits in an upstairs window and is a:
Linksys WRT300N
- Runs DD-WRT V24 - SP2 (Beta)
- Has original antennas
- Has the following properties set (among others, these are the interesting ones)
- Wireless - Basic Settings
- Mode: AP
- Network Mode: BG-Mixed
- Channel: 11 - 2.462 GHz
- SSID Brodcast: Enable
- Wireless - Advanced Settings
- TX Power: 71
- Wireless - Security
- Security Mode: WEP (I haven’t tested WPA2 with WDS yet, and I understand that WEP can be cracked easily)
- Wireless - WDS
- The three router’s MAC addresses are filled in, and are set to “LAN”
The three client WDS routers are also sitting in windows, and are on the first level of the buildings that they are in. They repeat the same SSID, and run on channel 11.
Buffalo WLI-TX4-G54HP
- Originally purchased as an ethernet bridge, it is now running DD-WRT V24 - SP2 (Beta)
- Replaced the stock antenna with a 9 dBi omni-directional
- Is on the 72.6m link
(2) Belkin F5D7230-4 routers
- WDS on the stock firmware works with DD-WRT, sweet!
- These are unmodified, running with their tiny fixed (two) omni-directional antennas
- One is on the 35.4m link, and the other on the 88.5m link
This setup has been going for weeks without an issue, and has served upwards of six families, a two person office, a fifteen to twenty person office, and a classroom with sixteen students.
We have other areas on the same property that have wireless access between buildings, but are nowhere near as complete as this arrangement. If we do end up using wireless to unify the property’s networks, then I will start looking into site to site links, multiple gateways, OLSR, and other mesh technologies. I have my doubts as to how well WDS scales. Has anyone had positive results with professional mesh solutions built on DD-WRT and Linksys hardware?
Posted by Karl Herrick on January 7th, 2010 in Wireless, Linux | No Comments »
Time Machine Size Limits
So I have this new My Book World Edition, and I set it up to allow for Time Machine backups. The problem? On OS X, Time Machine wants to eat up almost the entire amount of free space before it goes about deleting old files… (un)conveniently there is no option to restrict the size of the backups.
Never fear… I google’d a bunch and found that if you run the following command on the Mac doing the backups:
It doesn’t appear to do anything (or may possibly do something else that isn’t related to what I was after). 
So, I went about it in a different manner. If I clicked on the Time Machine icon (rotating clock) in the menu bar, and clicked “Enter Time Machine”… exited the GUI of Time Machine, and then opened terminal, I could do the following:
- Become root:
sudo -s
- Goto the /Volumes directory, and look for which folder is mounted for Time Machine backups:
cd /Volumes && ls -l
- Enter the folder that is mounted for Time Machine backups:
cd $Mount_Point_For_Backups
- Look for the .sparsebundle file that is being used for backing up the workstation:
ls -l
- Resize the sparsebundle file:
hdiutil resize -size 200g $hostname.sparsebundle
The sparse image is then resized, and Time Machine will report that there is only around 200 gigabytes total available space rather than around a terabyte (which is the original size of the drive).
Posted by Karl Herrick on January 2nd, 2010 in Backups, Apple, Linux, Bash | 1 Comment »
MBWE SSH access
Just setting up a My Book World Edition (1TB, WDH1NC10000) and would recommend the following steps after purchase for SSH access:
- Login to the MBWE’s “Network Storage Manager” by typing the unit’s IP address into a web browser and then authenticating with a valid username and password
- Click the “Advanced Mode” link
- Click the “Advanced” icon
- Check the “Enable” checkbox under the “SSH Access” area
- Click the “Submit” button
Now SSH into the MBWE using the username, “root”, with the default password, “welc0me”. After logging in, be sure to change passwords for the root user by issuing the command, “passwd”.
A few other things I noticed were necessary, if you want ssh access via public key authentication:
- Copy the contents of the public key file from the client (usually ~/.ssh/id_dsa.pub) to the MBWE on a new line under /root/.ssh/authorized_keys
- Login as root to the MBWE and issue the following command in the terminal: “chmod go-w ~/“. This was neccessary as when I tried to authenticate via public key, I was getting the following in /var/log/messages if I didn’t, “Authentication refused: bad ownership or modes for directory /root“
Posted by Karl Herrick on December 28th, 2009 in Linux, Bash | No Comments »
Office Compatibility
OpenOffice or Microsoft Office. Use either. It’s like OS X vs. Linux… whatever tool that is best for the job right?
Here’s how you can make the two play a little nicer…
OpenOffice
- Already reads and writes .docx, .xlsx, and .pptx (admittedly the .pptx support isn’t near as developed as the previous two formats mentioned, from my experiences at least)
- Download and install the following: Excel Viewer, Word Viewer, and PowerPoint Viewer 2007
- Download and install the following: Microsoft Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats
Users with older versions of Microsoft Office Products, including Word 2000/2002/2003, Excel 2000/2002/2003, PowerPoint 2000/2002/2003)
- Make sure your office products are updated with the latest service packs if any are available (check Microsoft Update)
- Download and install the following: Microsoft Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats
- Download and install the following: Sun ODF Plugin for Microsoft Office
Users of Microsoft Office 2007
- Download and install the following: Sun ODF Plugin for Microsoft Office
Posted by Karl Herrick on November 20th, 2009 in Apple, OpenOffice, Microsoft, Linux | No Comments »
The calendar has moved
So, I moved my calendars off of Apache/WebDAV and onto Google Calendar. Have I lost some control? Yes. Have I gained a huge amount of convenience. Definitely.
Google don’t fail me now!
Posted by Karl Herrick on November 1st, 2009 in Google, Linux | No Comments »