Daylight rules in Grandstream 2010 provisioning

Provisioning Grandstream 20xx phones via TFTP is easy, but one thing which causes problems is provisioning daylight saving values.

Normaly you should be able to set the P246 property to the correct value for your country/location.

It appears that inside the GXP, the firmware uses the same routine to decode the config file as is used to decode the data posted via a web browser. In other words, the data MUST BE URL-ENCODED.

For example, the following (current New Zealand 2007-onwards DST rule) will not work:

P246=9,1,7,2,0;4,1,7,3,0;60

But, if you URL-encode it, you will get:

P246=9%2C1%2C7%2C2%2C0%3B4%2C1%2C7%2C3%2C0%3B60

And guess what - the phone will accept it, and you're on your way :-)

If you've got python installed, you can encode things pretty easily. If you're using a different language, ask Google.

import urllib
print urllib.urlencode({'P246': '9,1,7,2,0;4,1,7,3,0;60'})

And here a online encoder
http://www.albionresearch.com/misc/urlencode.php

With that value you can set the correct daylight saving rules
for all grandstream phones in your network.

BTW: Perhaps someone should pass along this information to the fruits company, looks like iFruit is (not for the first time) having time problems ;)

Java application under windows 7

Developing java application fro windows 7 ?

Then look at this library, it might help integrate better with windows 7.
Not a "must have" but your users will appreciate it as a "nice to have".
And 50% of application functionality are "nice to have"

http://www.strixcode.com/j7goodies/

Your computer has no CD/DVD drive ?

A simple way to install most older and current linux systems is by creating a bootable USB stick.

Some distributions have a option to do this from the live CD, but you still have to first boot from that downloaded iso file.....

Here is a simple flexible solution:

http://unetbootin.sourceforge.net/

Just follow then instructions.

Beside this:

UNetbootin can also be used to load various system utilities, including:

• Parted Magic, a partition manager that can resize, repair, backup, and restore partitions.
• SystemRescueCD, a system repair, backup and recovery tool.
• Super Grub Disk, a boot utility that can restore and repair overwritten and misconfigured GRUB installs or directly boot various operating systems
• Dr.Web Antivirus, F-Secure Rescue CD, and Kaspersky Rescue Disk, which remove malware from Windows installs.
• Backtrack, a utility used for network analysis and penetration testing.
• Ophcrack, a utility which can recover Windows passwords.
• NTPasswd, a utility which can reset Windows passwords and edit the registry.
• Gujin, a graphical bootloader that can also be used to boot various operating systems and media.
• Smart Boot Manager (SBM), which can boot off CD-ROM and floppy drives on computers with a faulty BIOS.
• FreeDOS, which can run BIOS flash and other legacy DOS utilities.
• 
  

Group policy for password changing

Here some nasty info, when adding a password policy to a ADS:

• Password policy can only be set at the domain level.

If you like to have different password policies, you have to

• create a subdomain

or

• change to server 2008, where you can use Fin grained password poliy, that gives you the option for using different password policies.
  

or

• You look out for a a 3rd party tool

What might be the technical reason for this ?

The whole login/authorization of windows (before windows 2008/Vista) is based on NTLM, which basically means you are logging on into a NT style domain.
So all users in that domain have the same (NT style) password restriction.

If all your systems are Windows 2008 or newer, then kerberos is used for authentication/logon, and here apparently password policies are applied as normal users would think.

Upgrading CentOS 5.4 to 5.5 32Bit DomU on a Xen 64 Bit Dom0

Normally upgrading centos is very simple by doing a
yum update

But when you run centos as a 32bit DomU under a 64 Bit Dom0 server, you will receive strange error messages.
This is due to the fact, that the rpm command looks at the installed kernel, and that one is a 64bit build. So it then trys to move everything to 32 AND 64 bit.
To prevent this, just create the file /etc/rpm/platform and place the line:

i686-redhat-linux

in it.
After this, all the yum rpm commands work fine, since they are fixed to the i386/i686 platform. No confusion about the 64bit kernel.

ipv6 in the wild

In the last year we did many steps toward ipv6 enabling our networks and servers.
Many things are simple, but there are also many pitfalls.

Here some infos about ipv6 in Ubuntu/Debian

- The Ubuntu distribution 9.04 and newer have good IPv6 support, most applications work with ipv4 and ipv6. Some applications however have problems with ipv6 addresses in some places. Here a upgrade to the most recent 10.10 release solves many issues.

- Debian, yeah, most things work fine in lenny, you can do most things you need, but there are still a few places where you may stumble. The real "full" ipv6 support is coming up in squeeze.

Here a two places where you might struggle:

- Assigning a static IPv6 address in debian lenny just does not work....
Nothing to worry about on workstations/desktops, but on firewalls and servers... it would be nice to always have the same ipv6 address assigned.
The reason for the problem is, that when the eth0 interface (or any other) is activated, the kernel module ipv6 is not yet loaded. So it's not possible to assign the ipv6 settings specified in the /etc/network/interfaces file.
The simplest solution is to just add ipv6 to the file /etc/modules (and rebuild the initramfs), that way ipv6 is directly loaded on boot and everything works as intended.

- RSYNC has only partial ipv6 support.
What does this mean ?
Rsync is able to resolve host names into ipv6 addresses and then connect to them via ipv6.
But if you with to specify the ipv6 address of the host directly on the commandline, then it fails parsing the address.
The simplest way to solve the problem is to install the rsync from the debian backports.

Don't forget, ipv4 addresses are running out in the next year, so prepare slowly to add ipv6 support to your network.
You don't have to do it in a big-bang way, rather just implement it step-by-step.

Collect linux statistics with collectd

Collectd is a great tool to collect various parameters of a running linux installation.

It can monitor disk space, cpu load, temperatures and much more.

One thing to note, is that collectd can cause system load by itself.
To prevent this, enable caching in the rddtools.

For more details read on in this post:

https://jeremy.visser.name/2010/02/23/enable-caching-in-collectd/