Author: David (admin)

Hardware

Review: Belkin KVM Omniview 5216K

A few months ago I got myself quite an expensive new device: a Belkin Omniview 5216K, model no F1DP216G. With this device, I'm supposed to be able to access the KVM of up to 16 servers. I can install them servers remotely (over PXE or virtual media), configure the system BIOS. All without going to the data center.

This way I can offer a better service on my servers from anywhere in the world.

The specs according to Belkin

  • High-Performance Remote Access Access, switch, view, and control faster than before. Switch from one remote server to another instantly. Quicker performance over Internet and congested networks.
  • Web Browser-Based The Switch allows you to access your KVM switch and all connected servers from any computer connected to the LAN, WAN, or Internet using Firefox or Microsoft Internet Explorer.
  • Out of Band--BIOS-Level Access The Switch allows you to remotely access the basic input/output system (BIOS) of your servers to make changes and perform reboots, regardless of network connectivity or server condition.
  • User-Friendly Interface The web-based interface allows you to set up and change the Switch functions quickly and easily through your web browser, without having to install additional software onto your servers.
  • Remote Serial Access The Switch provides support for up to two serial devices, such as a managed power distribution unit (PDU), so you can remotely perform hard reboots of your servers.
  • Virtual Media Technology The Switch provides virtual media support for up to two servers. This allows remote users to copy files for their USB or CD-ROM drive to a target server that may be anywhere in the world.
  • Enhanced Security The IP device provides 128-bit Secure Sockets Layer (SSL) authentication and password protection to prevent unauthorized access to your servers and protect data transferred over the Internet.
  • Scalable Centralized Management Additional Switches can be added as your data center grows and the entire inventory can be managed under the Belkin Central Access Appliance 5000HQ.
  • Video Resolution The Switch supports video resolutions of up to 1600x1200@75Hz for both local and remote consoles.
  • Flash-Upgradeable Flash upgrades allow you to obtain the latest firmware updates for your Switch. These firmware updates ensure that the Switch is compatible with the latest devices.

My experience with the device

Crashes

Well, let's just say I'm happy I got myself an Ingrasys iPoman 1201 remote power switch as well.

Before I upgraded the KVMs firmware, the devices wasn't usable at all. After the upgrade to the newest firmware, the device got a little better. But still, the Mean Time Between Failure (MTBF) is literaly just minutes. In the last 2 hours, I had to switch off the power several times. And there hasn't been a single time in these 2 hours that I could use the KVM switch for more than 5 minutes without it crashing.

I actually made a shell script to reset the KVM switch. When resetting the switch, I'm pinging it to see if I can reach it again. On the last reset I just did, the device stayed available for only 14 seconds(!!).

Linux
Of course, the device can't handle Linux clients. So I have to run a Windows instance in VMWare player to access the device.

Keys stuck

Update: I almost forgot to mention that I really can't type one sentence without having a key stuckkkkkkkkkkkkkkkkkkkkkkkkkkkkkk. ARGH!

Conclusion

It's crap. Don't buy one. The idea of KVM-over-IP is great, but if the device locks me out by crashing so often, it's absolutely worthless.

I'm calling Belkin and/or the store as soon as the holidays are over to see if I can return the device.

Update: The thing has now officially died. While starting up, the lights walk to indicate it's initializing. Since yesterday, the initializing never stops. I can't reach it over IP anymore, nor locally by connecting a monitor to the VGA connector...

Update: More news on my broken KVM switch

© GeekLabInfo Review: Belkin KVM Omniview 5216K is a post from GeekLab.info. You are free to copy materials from GeekLab.info, but you are required to link back to http://www.geeklab.info

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IT

Printing from a CUPS server to Windows 7

A colleague of mine has some family issues that require him to be home more often. However, work continues. So he started working at home with a laptop. Nothing special about that. What is special, is that we're running a piece of software ("RR") that has old-style telnet-like terminals, which is sending it's print jobs straight to the printer.

His laptop has a direct VPN connection to the company network, but his printer doesn't.

Network info

The old software ("RR") is running on a pretty new RHEL 5.6 installation. It uses CUPS to queue and deliver print jobs. In my situation, the RR printer has zero printers configured, there's another Linux server that has all printers configured and broadcasts those printers over the network. But you could leave that print server out.

Problem

RR cannot reach the printer directly. But it can reach the laptop, which is running Windows 7 Professional. I searched for an IPP server that I could install on Windows, so that the printserver could use that to relay messages to the local printer, but I couldn't find any.

Solution

Windows 7 still has the option to install an lpd server. It's not installed by default, but it's very simple to install.

Windows setup:

  • In the Windows 7 Control Panel
  • Go to the "Programs and Features"
  • Click "Turn Windows Features on or off"
  • Turn on the LPD protocol.
  • Now go to the "printers" and share all printers you want to share.
  • Don't use long names and names with spaces, like "HP Laserjet 4200 Series", which are hard to setup on the client. Use something short like hplj4200.

Client setup:
Now you can setup the client to print to lpd://[ip-or-hostname-of-client]/[printername], for example lpd://10.10.10.17/hplj4200

If you can't get it to work, please check printer permissions and the firewall of the Windows 7 machine, which must have port 515 open.

© GeekLabInfo Printing from a CUPS server to Windows 7 is a post from GeekLab.info. You are free to copy materials from GeekLab.info, but you are required to link back to http://www.geeklab.info

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IT

WordPress: custom links on plugin page

Since WordPress 2.8, you can easily add your own links to the plugin page. This can be useful to jump right to the settings of the plugin. Example code:

function set_plugin_meta($plugin_meta, $plugin_file, $plugin_data, $status){
if (plugin_basename(__FILE__)!=$plugin_file) return $plugin_meta;
return array_merge( $plugin_meta, array( sprintf( '<a href="options-general.php?page=%s">%s</a>', $plugin, __('Settings') ) ));
}
add_filter( 'plugin_row_meta', 'set_plugin_meta', 10, 2 );

Two other interesting plugin hooks are:

do_action( 'after_plugin_row', $plugin_file, $plugin_data, $status );
do_action( "after_plugin_row_$plugin_file", $plugin_file, $plugin_data, $status );

These are both run after the row was printed.

© GeekLabInfo WordPress: custom links on plugin page is a post from GeekLab.info. You are free to copy materials from GeekLab.info, but you are required to link back to http://www.geeklab.info

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IT

An Asterisk 1.8 fax server

To start, I setup a clean, minimal Fedora 15 installation.

Install requirements

After installation, we install a few more tools that we need:
yum install asterisk asterisk-fax #base
yum install perl-Email-MIME libtiff-tools #for mailer script
yum install telnet mc vim ntp rsync #for convenience and backup

Synchronize your time:
sntp -s pool.ntp.org

Configuration

On a clean asterisk installation, we only edit a few files.

sip.conf
Edit /etc/asterisk/sip.conf and make the following changes:

  • Look for ;faxdetect=yes and uncomment it by removing the ;
  • Somewhere under [global] put your register string. For example:
    register => myUsername:myPassword@12.34.56.78/31331234567
    In this example 12.34.56.78 is the ip of my SIP provider and 31331234567 my internationalized fax number.
  • At the bottom, add the following lines:
    [trunk-geeklab-9]
    username=myUsername
    type=peer
    secret=myPassword
    qualify=yes
    host=12.34.56.78
    canreinvite=yes
    context=geeklab-fax
    insecure=invite

extensions.conf
To /etc/asterisk/extensions.conf add the following lines:
[geeklab-fax]
exten => 331234567,1,Goto(inboundfax,s,1)
;This is the DID number my provider rings. I would
;prefer 3133123... or 033123... but that's just the
;way it is. Your provider may use another format.

[inboundfax]
;I could have merged this with [geeklab-fax] but i decided not to.
exten => s,1,NoOp(**** FAX RECEIVED from ${CALLERID(num)} ${STRFTIME(${EPOCH},,%c)} ****)
exten => s,n,Set(FAXOPT(ecm)=yes)
exten => s,n,Set(FILENAME=fax-${STRFTIME(${EPOCH},,%Y%m%d-%H%M%S)}-${CALLERID(num)})
exten => s,n,Set(FAXFILE=${FILENAME}.tif)
exten => s,n,Set(FAXOPT(ecm)=yes)
exten => s,n,Set(FAXOPT(headerinfo)=Received by MYCOMPANY ${STRFTIME(${EPOCH},,%Y-%m-%d %H:%M)})
exten => s,n,Set(FAXOPT(localstationid)=0331234567)
exten => s,n,Set(FAXOPT(maxrate)=14400)
exten => s,n,Set(FAXOPT(minrate)=2400)
exten => s,n,NoOp(FAXOPT(ecm) : ${FAXOPT(ecm)})
exten => s,n,NoOp(FAXOPT(headerinfo) : ${FAXOPT(headerinfo)})
exten => s,n,NoOp(FAXOPT(localstationid) : ${FAXOPT(localstationid)})
exten => s,n,NoOp(FAXOPT(maxrate) : ${FAXOPT(maxrate)})
exten => s,n,NoOp(FAXOPT(minrate) : ${FAXOPT(minrate)})
exten => s,n,NoOp(**** RECEIVING FAX : ${FAXFILE} ****)
exten => s,n,ReceiveFAX(/var/spool/asterisk/fax/${FAXFILE})
exten => s,n,Hangup()
exten => h,1,NoOp(FAXOPT(ecm) : ${FAXOPT(ecm)})
exten => h,n,system(/usr/local/bin/fax-process.pl --to yourname@geeklab.info --from fax@geeklab.info --subject "Fax from ${URIENCODE(${CALLERID(number)})} ${URIENCODE(${CALLERID(name)})}" --attachment ${FILENAME}.pdf --type application/pdf --file ${FAXFILE});

Inbound fax notification

When you get a fax, you'll probably want it in you mailbox. Download fax-process.txt and move it to /usr/local/bin/fax-process.pl. Make it executable using chmod 755 /usr/local/bin/fax-process.pl. If you haven't disabled SELinux, change the files security context by running: chcon system_u:system_r:asterisk_t:s0 fax-process.pl

Firewall

You won't get any calls if the firewall drops them. You may want a complex firewall. But since I'm using this virtual machine as a dedicated fax, I allow all from my SIP host and nothing from other hosts. Edit /etc/sysconfig/iptables to reflect your preferences. Mine are:
*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [59:6844]
-A INPUT -s 12.34.56.78 -p tcp -m tcp ! --dport 22 -j ACCEPT
-A INPUT -s 12.34.56.78 -p udp -m udp -j ACCEPT
-A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
-A INPUT -p icmp -j ACCEPT
-A INPUT -i lo -j ACCEPT
-A INPUT -p tcp -m state --state NEW -m tcp -s my.ho.me.ip --dport 22 -j ACCEPT
-A INPUT -j REJECT --reject-with icmp-host-prohibited
-A FORWARD -j REJECT --reject-with icmp-host-prohibited
COMMIT

You're done

Start asterisk by running service asterisk start and you're good to go.

© GeekLabInfo An Asterisk 1.8 fax server is a post from GeekLab.info. You are free to copy materials from GeekLab.info, but you are required to link back to http://www.geeklab.info

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IT

Dracut: add drivers to your initrd

My HP 8150w laptop has this neat lis3lv02d accelerometer to be able to detect when it's falling and to park the harddisk to prevent damage. I use this instrument to detect whether I'm on the road or at the office. This way, I can set preferences at boot-time, even before the network settings are loaded.

I have added a few scripts to my initrd, which are not very interesting. But what is, is the driver required to do this.

I created a file named /etc/dracut.conf.d/tilt.conf which contains:
add_drivers="$add_drivers hp_accel lis3lv02d input_polldev"

After creating a new initrd by running dracut, my scripts can see the x/y/z tilt of the machine by reading from /sys/devices/platform/lis3lv02d/position

© GeekLabInfo Dracut: add drivers to your initrd is a post from GeekLab.info. You are free to copy materials from GeekLab.info, but you are required to link back to http://www.geeklab.info

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Hardware

Find the Dell Service Tag Remotely

Windows with VNC/RDP

If you can login to the computer over VNC or RDP, you can use wmic to find the service tag:
start > run > cmd
On the command line, enter:
wmic bios get serialnumber

Windows without VNC/RDP

If you cannot login to the computer over VNC or RDP, you can still use wmic to find the service tag:
start > run > cmd
On the command line, enter:
wmic /node:computer-name-here bios get serialnumber
You may need to use /user:yourusername and /password:yourpassword to get access to the remote computer. Running wmic /? gives a pretty good manual on what wmic can do.

Other uses of wmic

wmic is a very useful tool for a lot of stuff. For instance wmic csproduct can tell you exactly what model the computer is and wmic nic list shows useful information about your network.

Linux

Under Linux, you can run dmidecode -s system-serial-number to get the serial number. This can be done locally or over ssh.

© GeekLabInfo Find the Dell Service Tag Remotely is a post from GeekLab.info. You are free to copy materials from GeekLab.info, but you are required to link back to http://www.geeklab.info

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IT

Lovelock: Mozilla as default browser from Thunderbird

Last week, I upgraded to Fedora 15 (codename: Lovelock). One of the new annoying "features" is that Google Chrome somehow got to be the default browser when I click a link from Firefox.

I Google'd around, and couldn't find how to fix it. So I decided to strace it. Apparently, Thunderbird launches gvfs-open to open a browser. Again I straced the command "gvfs-open https://www.geeklab.info", and found that it opens /usr/local/share/applications/defaults.list, which referred to google-chrome.desktop instead of mozilla-firefox.desktop. My file now contains:

[Default Applications]
text/html=mozilla-firefox.desktop
text/xml=mozilla-firefox.desktop
application/xhtml_xml=mozilla-firefox.desktop
x-scheme-handler/http=mozilla-firefox.desktop
x-scheme-handler/https=mozilla-firefox.desktop
x-scheme-handler/ftp=mozilla-firefox.desktop

And it's fixed! :-)

Update: Since some crap keeps changing this file, i just made the file immutable. The command chattr +i /usr/local/share/applications/defaults.list prevents programs that would normally have permissions to edit the file to be blocked.

© GeekLabInfo Lovelock: Mozilla as default browser from Thunderbird is a post from GeekLab.info. You are free to copy materials from GeekLab.info, but you are required to link back to http://www.geeklab.info

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