Author: rahul

ZK spreadsheet is an online spreadsheet which enables users to import and export excel files and edit excel files within the browser. This can be thought to be similar to Google Spreadsheet. Only that it is open source and can be installed on your own server. Another very similar open source product which I came across was Sheetster but the setup was not very straight forward and also I was not really impressed with the UI and functionality.

Below, I give the steps for installing ZK spreadsheet on Debian Lenny:

1. First we install tomcat5.5.

   # apt-get install tomcat5.5 tomcat5.5-webapps tomcat5.5-admin

   Accessing http://localhost:8180/ should display the default Tomcat home page.

2. Download ZK Spreadsheet Demo (Executable) from http://code.google.com/p/zkspreadsheet/. During the time of writing this article, the beta version did not have Save and Import features enabled. So I proceeded to download the stable version from http://sourceforge.net/projects/zss/files/ZK%20Spreadsheet/. Either way the procedure for installation is the same.
3. Extract it and move the war files to webapps directory.

   # unzip zk-spreadsheet-demo-2.0.0-Beta.zip
   # cd zk-spreadsheet-demo-2.0.0-Beta
   # mv zssapp.war zssdemo.war /var/lib/tomcat5.5/webapps/
   

4. Make the below modifications in /etc/tomcat5.5/policy.d/03catalina.policy.

   ...
   ...
   ...
   // These permissions apply to JULI
   grant codeBase "file:${catalina.home}/bin/tomcat-juli.jar" {
   ...
   ...
   ...
       permission java.io.FilePermission "${catalina.base}${file.separator}webapps${file.separator}zssapp${file.separator}WEB-INF${file.separator}classes${file.separator}logging.properties", "read";
       permission java.io.FilePermission "${catalina.base}${file.separator}webapps${file.separator}zssdemo${file.separator}WEB-INF${file.separator}classes${file.separator}logging.properties", "read";
   };
   ...
   ...
   ...
   //added for zssapp webapp
   grant codeBase "file:${catalina.base}/webapps/zssapp/-" {
          permission java.security.AllPermission;
   };
   

5. Restart tomcat5.5.

   # /etc/init.d/tomcat5.5 restart

   The ZK spreadsheet should now be accessible at http://localhost:8180/zssapp/ and the demo at http://localhost:8180/zssdemo/.

6. The spreadsheet documents are stored in the zssapp web application directory. To protect others from reading this data, you need to perform the below two steps:
   • First limit access to this directory in the filesystem.

     # chmod 700 /var/lib/tomcat5.5/webapps/zssapp/

   • Next add some kind of authentication for the webapp. The possible authentication mechanisms in Tomcat 5.5 are mentioned in http://tomcat.apache.org/tomcat-5.5-doc/realm-howto.html which can be used for reference. A sample configuration can be found at http://www.jguru.com/faq/view.jsp?EID=1131436.

If you face any issues or have any queries reg. ZK Spreadsheet, you can post in the forum at http://www.zkoss.org/forum/.

References:

http://ostatic.com/question/open-source-web-spreadsheet
http://en.wikipedia.org/wiki/List_of_spreadsheet_software#Online_spreadsheets
http://en.wikipedia.org/wiki/List_of_online_spreadsheets

How to setup Apache Tomcat 5.5 on Debian Etch

http://www.mkyong.com/tomcat/tomcat-javasecurityaccesscontrolexception-access-denied-loggingproperties-read/
http://www.zkoss.org/forum/listComment/9143

All-In-One Tools

Hardware Lister:

Hardware Lister can be used for getting all the hardware information of a system. Some example usage are given below:

# apt-get install lshw lshw-gtk
# lshw (Displays detailed hardware information)
# lshw-gtk (Gives a nice graphical view of the hardware information) 
# lshw -short (Lists hardware in a compact format)
# lshw -class disk -class storage (Lists all disks and storage controllers in the system)
# lshw -html -class network (Lists all network interfaces in HTML)

Refer to the link in the References section to get the complete list of device classes.

Dmidecode:

Another tool which serves a similar purpose is dmidecode.

# apt-get install dmidecode
# dmidecode (Display detialed hardware information)
# dmidecode --type bios (Display information related to BIOS)

The various types permitted can be got from the manpage of dmidecode.

Component Information

Most of the below commands should be run as root.

BIOS:
Retrieve BIOS information such as Vendor, Version, Characteristics, etc.

# dmidecode --type bios
# biosdecode

System:
Retrieve a lot of useful information such as Manufacturer, Product Name, Version, Wake-up Type, etc.

# lshw -class system
# dmidecode --type system

Motherboard:
Prints motherboard information such as Manufacturer, Product Name, Serial Number and also information of onboard devices.

# dmidecode --type baseboard
# lspci

Processor:
Get processor information such as the Manufacturer, Version, etc.

# lshw -class processor
# dmidecode --type processor
# cat /proc/cpuinfo

Memory:
Get memory information such as the numver of memory slots, RAM information in each slot (if installed), etc.

# lshw -class memory
# dmidecode --type memory
# cat /proc/meminfo
# free -m

PCI/PCIe Slots and USB devices:
Retrieve information about onboard PCI slots, attached USB devices, etc.

# lshw -class bus
# dmidecode --type connector --type slot
# lspci
# lsusb

Hard Disk(s):
Retrieve hard disk(s) details such as size, model, etc.

# lshw -class storage -class disk --class volume
# fdisk -l
# hdparm -I /dev/sda

VPD:
VPD stands for “vital product data” information that can be found in almost all IBM and Lenovo computers.

# vpddecode

System Hardware Snapspot

This is especially useful when giving your laptop or desktop to service centres for repair. You can take a snapshot before and after and compare them to ensure that no parts have been replaced. It is highly recommended that you run the below commands as root.

# lshw -short > lshw.short
# lshw -xml > lshw.xml
# lshw -json > lshw.json
# lshw -html > lshw.html

References

http://www.cyberciti.biz/faq/linux-list-hardware-information/
http://www.cyberciti.biz/tips/querying-dumping-bios-from-linux-command-prompt.html
http://legroom.net/2010/05/05/get-biosmotherboard-info-within-linux
http://www.cyberciti.biz/tips/linux-command-to-gathers-up-information-about-a-linux-system.html
http://www.cyberciti.biz/faq/find-hard-disk-hardware-specs-on-linux/

http://www.nongnu.org/dmidecode/
http://ezix.org/project/wiki/HardwareLiSter#Deviceclasses

After spending almost a day in trying to configuring my dd-wrt router as an OpenVPN client and reading many complicated guides, I found a really simple way to configure OpenVPN. It is necessary that you have optware set up on your router. For setting up Optware, kindly read Optware, The Right Way.

This configuration has been tested with DD-WRT K26 svn 14569 mega build (of Brainslayer) on a WRT610Nv1 router. Configuration of OpenVPN server is beyond the scope of this article. But here is an excellent article on how to setup OpenVPN server in Debian.

1. Install openvpn using ipkg.

   # ipkg-opt update
   # ipkg-opt install openvpn
   

2. Dump your vpn configuration file in /opt/etc/openvpn/. Let us assume the name of the configuratoin file is example.vpn.conf. You might have to make certain changes in the configuration file such as:
   • Setting the name of the user and group in the config file to that which are existing on the router. ‘nobody’ user and ‘nobody’ group exist on the system so you can use these. If you intend to use the route-down.sh script (see below), you will have to set these to ‘root’ user and ‘root’ group. For route-up.sh script though, it is fine if you use ‘nobody’ user and ‘nobody’ group because the downgrade of privileges by openvpn client happens after the route-up.sh script is called.
   • Setting the correct paths for key and certificate files in example.vpn.conf.
3. Test if openvpn connection is being established by running the below command.

   # /opt/sbin/openvpn --cd /opt/etc/openvpn --config example.vpn.conf
   

   If the connection is being established properly you may proceed to the next step.

4. Set up the scripts for allowing machines behind the dd-wrt router to access clients in the VPN network and for clients in the VPN network to access the dd-wrt router.

   /opt/etc/openvpn/route-up.sh:

   # Enable machines behind the router to access the clients in VPN network
   /usr/sbin/iptables -I POSTROUTING -t nat -o tun0 -j MASQUERADE
   
   # Enable the clients in the VPN network to access the router
   /usr/sbin/iptables -I INPUT -t filter -i tun0 -j ACCEPT
   

   /opt/etc/openvpn/route-down.sh:

   # Disable machines behind the router to access the clients in VPN network
   /usr/sbin/iptables -D POSTROUTING -t nat -o tun0 -j MASQUERADE
   
   # Disable the clients in the VPN network to access the router
   /usr/sbin/iptables -D INPUT -t filter -i tun0 -j ACCEPT
   

   Test the connection again.

   # chmod 755 route-up.sh route-down.sh
   # /opt/sbin/openvpn --cd /opt/etc/openvpn --config example.vpn.conf --script-security 2 system \
   --route-up /opt/etc/openvpn/route-up.sh --down /opt/etc/openvpn/route-down.sh
   

   Note: For advanced users who can configure OpenVPN server, it is possible for the clients in the VPN network to access the private subnet behind the router. Roughly summarizing, this can be achieved by setting up internal routes in the OpenVPN server to redirect all traffic to the private subnet to the router, pushing additional routes to the VPN clients, and allowing forward/masquerading in the router.

5. In this last step, we enable openvpn client to connect automatically during startup. Edit /opt/etc/init.d/S20openvpn and make the following changes:
   • Comment the statement “return 0” so that we can keep run openvpn as a daemon.
   • Set the proper path for killall command (/usr/bin/killall).
   • Add the line “/opt/sbin/openvpn –daemon –cd /opt/etc/openvpn –config example.vpn.conf –script-security 2 system –route-up /opt/etc/openvpn/route-up.sh –down /opt/etc/openvpn/route-down.sh” at the bottom.

   /opt/etc/init.d/S20openvpn:

   #!/bin/sh
   #
   # Startup script for openvpn as standalone server
   #
   
   # Make sure IP forwarding is enabled
   echo 1 > /proc/sys/net/ipv4/ip_forward
   
   # Make device if not present (not devfs)
   if ( [ ! -c /dev/net/tun ] ) then
     # Make /dev/net directory if needed
     if ( [ ! -d /dev/net ] ) then
           mkdir -m 755 /dev/net
     fi
     mknod /dev/net/tun c 10 200
   fi
   
   # Make sure the tunnel driver is loaded
   if ( !(lsmod | grep -q "^tun") ); then
           insmod /opt/lib/modules/tun.o
   fi
   
   # I you want a standalone server (not xinetd), comment out the return statement below
   #return 0
   
   
   ## This is for standalone servers only!!!!
   # Kill old server if still there
   if [ -n "`pidof openvpn`" ]; then
       /usr/bin/killall openvpn 2>/dev/null
   fi
   
   # Start afresh - add as many daemons as you want
   #/opt/sbin/openvpn --daemon --cd /opt/etc/openvpn --config openvpn.conf
   /opt/sbin/openvpn --daemon --cd /opt/etc/openvpn --config example.vpn.conf --script-security 2 \
                     --route-up /opt/etc/openvpn/route-up.sh --down /opt/etc/openvpn/route-down.sh
   
   # [EOF]
   

   Test the script.

   # chmod u+x /opt/etc/init.d/S20openvpn
   # /opt/etc/init.d/S20openvpn
   

6. Rebooting the router should now get you connected automatically to your VPN network.