Archive forTechnology

Multiple RBL check – DNS Blacklist Entries

In case you are a system administrator and you are running your own mail or a web server, it would be good to know in time whether the IP address of your server has been blacklisted in the Internet. What does that mean? It means your server has been compromised and it sending lot of unwanted SPAM mail and in no time users would complain that their mail not being accepted by their recipients.

There are a lot of websites online, some paid and some free, which would provide you the necessary information stating whether your IP is blacklisted or not, but the drawback is that this online websites allows IP’s to be scanned on minimum hourly basis. This might be too late for a system administrator wherein you can find yourself in the tip of the knife as mails would start bouncing back. So what is the solution?

One can use the `host` command or `dig`to find this out and then create a automated script run it in cron.

As an example, let us take into consideration, your IP is A.B.C.D, so your reverse would be D.C.B.A. You need to check against frequently used SPAM databases. Let use take `` as one of the domain as this is most frequently by users for SPAM checks.

root@ophiophagus:~$ host -t a has address

root@ophiophagus:~$ dig

; <<>> DiG 9.8.1-P1 <<>>
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 31887
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 21, ADDITIONAL: 0

; IN A


;; AUTHORITY SECTION: 86270 IN NS 86270 IN NS 86270 IN NS 86270 IN NS 86270 IN NS 86270 IN NS 86270 IN NS 86270 IN NS 86270 IN NS 86270 IN NS 86270 IN NS 86270 IN NS 86270 IN NS 86270 IN NS 86270 IN NS 86270 IN NS 86270 IN NS 86270 IN NS 86270 IN NS 86270 IN NS 86270 IN NS

;; Query time: 4 msec
;; WHEN: Sat Jun 28 20:06:42 2014
;; MSG SIZE rcvd: 405

If the response is an address in the loopback range, it means that it has been listed against the particular domain. Time for de-listing and check what caused the IP to be blacklisted.

Frequently used SPAM databases creates a DNS entry on their local nameserver making all RDNS entries resolve to their local IP.

Automate PHP script to find out the blacklisted IP:

File name: rblcheck.php

$ips=array("D.C.B.A"); // Add more IP's comma separated
$handle = fopen("domain-check-for-rbl.txt","r");
while (($line = fgets($handle)) !== false) {
foreach($ips as $ip){
$result = shell_exec("host -t a ".$ip.".".trim($line)." >/dev/null;echo $?");
$message = $message."\n".$ip." Blacklisted in ".trim($line)."\n";

Crontab entry running every 5 minute:

0/5 * * * * /usr/bin/php /rblcheck.php 2>&1

Filename: domain-check-for-rbl.txt


Gmail down

Oops, Gmail was done for some time.

Gmail Offline


BEL Tablet PC


1. Srinivas R.
2. Rajesh R.

I had an opportunity to get hold of a non functioning BEL Tablet PC which was launched for the Ministry of Rural Development’s poverty survey. The tablet was manufactured at BEL’s Bangalore plant and it had received huge orders for manufacturing the same.

Look and Feel:

The tablet as a whole with the keyboard and leather carry case looks like a diary, heavy for it’s size. You can remove all this an just carry it with the stylus, which fits into the tablet itself. The added advantage is the additional battery pack which comes in handy when you require more life out of it, but compared to what is available in the market now, this model seems out dated. Being an indigenously built product, I would love to see it’s future in the market.

Bel Tablet PC with battery pack


1. 7 inch display with a Stylus
2. Android 2.2 version
3. Solar-backed battery?
4. A mini USB keyboard
5. SD card slot
6. 2 USB ports
7. RJ 45 slot
8. Microphone/Speaker jack
9. An external battery pack with a charger.

Note: Battery pack can be charged by the big pin Nokia Mobile charger also.

Problem: The dreaded blue screen error.
Solution: There were a lot of solutions available in the forums but none seemed to work for me.
Support: Since there was a warranty sticker on the tablet we called up BEL customer care and they informed that one need to carry the equipment to the place from where it is brought from. They also questioned from where one got hold of it, since it is still not handed over to the masses. WT?
Solution: Open up the tablet and start debugging.

Electronics Inside:

I don’t understand the components wired in the circuit, but Srinivas have taken a picture of the same for reference.

BEL Tablet Circuit Board

The components that matter for debugging are marked,


Trail 1: Tried removing the display cable and fixing it back. Powering on, same blue screen error.

Trial 2: Removed the mini SD card that is used for booting and and inserted our card with L Ubuntu ( on it. Powering on, same blue screen error.

Trail 3: Re-inserted the old mini SD card having Android OS. Powering on the tablet while holding the back button and the power button simultaneously for 1-2 minutes. Something new appearing on the screen,

SD card detected
Updating kernel
Wait for 2 minutes
System updated

Note: Don’t stop pressing those keys until the whole procedure is over.

BEL Tablet Booting after re-fixing

Viola, the tablet is booting. One can see the BEL logo after which Android OS booting. Tried using external keyboard/mouse, all seem to be functional except the stylus, but we are not sure whether this was working before or not, so left like that. Overall, seemed like a loose connectivity.

Comments (7)

Tata Indica Xeta GLS

Going by the price rise in petrol, it was a tough choice to make whether it is a wise choice to buy a petrol car. But giving the extra amount you spent in buying the diesel car upfront is almost equivalent to the amount that you would spend in running the petrol car for some years. This is with consideration that the daily commute is less 50 kms. Moreover, in case of a petrol car the maintenance headache is much less.

So, taking into considerations of all this factors, I gifted myself the car on 19th May, 2012 with a 1.4L engine.

Tata Indica Xeta GLS


Setting up an SMS Gateway on Ubuntu 10.04

How to do it? Below list the procedure.

Install the following packages,

root@ophiophagus:~# sudo apt-get install gammu gammu-smsd libgammu7 libgsmsd7

Attached the handset to your computer via USB, Serial etc. and on the other terminal, do the following,

root@ophiophagus:~# tail -f /var/log/syslog
May 22 21:37:30 ophiophagus kernel: [42750.936095] usb 7-1: new full speed USB device using uhci_hcd and address 11
May 22 21:37:30 ophiophagus kernel: [42751.166604] usb 7-1: configuration #1 chosen from 1 choice
May 22 21:37:30 ophiophagus kernel: [42751.223525] cdc_acm 7-1:1.1: ttyACM0: USB ACM device
May 22 21:37:30 ophiophagus kernel: [42751.227023] usb 7-1: bad CDC descriptors
May 22 21:37:30 ophiophagus kernel: [42751.230408] usb 7-1: bad CDC descriptors
May 22 21:37:30 ophiophagus modem-manager: (ttyACM0) opening serial device…
May 22 21:37:30 ophiophagus NetworkManager: SCPlugin-Ifupdown: devices added (path: /sys/devices/pci0000:00/0000:00:1d.1/usb7/7-1/7-1:1.11/net/usbpn0, iface: usbpn0)
May 22 21:37:30 ophiophagus NetworkManager: SCPlugin-Ifupdown: device added (path: /sys/devices/pci0000:00/0000:00:1d.1/usb7/7-1/7-1:1.11/net/usbpn0, iface: usbpn0): no ifupdown configuration found.
May 22 21:37:30 ophiophagus modem-manager: (ttyACM0): probe requested by plugin ‘Nokia’
May 22 21:37:31 ophiophagus modem-manager: (ttyACM0) closing serial device…
May 22 21:37:31 ophiophagus modem-manager: (Nokia): GSM modem /sys/devices/pci0000:00/0000:00:1d.1/usb7/7-1 claimed port ttyACM0
May 22 21:37:31 ophiophagus modem-manager: Added modem /sys/devices/pci0000:00/0000:00:1d.1/usb7/7-1
May 22 21:37:31 ophiophagus modem-manager: Exported modem /sys/devices/pci0000:00/0000:00:1d.1/usb7/7-1 as /org/freedesktop/ModemManager/Modems/12
May 22 21:37:31 ophiophagus NetworkManager: (ttyACM0): new GSM device (driver: ‘cdc_acm’)
May 22 21:37:31 ophiophagus NetworkManager: (ttyACM0): exported as /org/freedesktop/NetworkManager/Devices/15
May 22 21:37:31 ophiophagus NetworkManager: (ttyACM0): now managed
May 22 21:37:31 ophiophagus NetworkManager: (ttyACM0): device state change: 1 -> 2 (reason 2)
May 22 21:37:31 ophiophagus NetworkManager: (ttyACM0): deactivating device (reason: 2).
May 22 21:37:31 ophiophagus NetworkManager: (ttyACM0): device state change: 2 -> 3 (reason 0)

This will tell you to which device file the device is attached. In my case it was ttyACM0.

One need to create a file with the following configuration,

root@ophiophagus:~# vi .gammurc

The other option to create this file is to use the `gammu-config` command to configure it.

SMS Gateway Gammu Config

Viola, you are done with the configuration. You can test by the following,

root@ophiophagus:~# gammu –identify
Manufacturer : Nokia
Model : unknown (ABCD)
Firmware : N012345678
IMEI : 012345678901234
SIM IMSI : 012345678901234

root@ophiophagus:~# echo “SMS Testing” | gammu –sendsms TEXT 1234567890
If you want break, press Ctrl+C…
Sending SMS 1/1….waiting for network answer..OK, message reference=168

The `gammu` manual lists a lot of options for it’s configuration.

The above does work with only some mobile. I had tried at least 3 mobiles before succeeding. You can check the whole mobile database on the following link,

Important notice: Network manager has tendency to lock your GSM device once you start your GSM Internet connection. The device stays locked even after you disconnect so you must make sure that `enable mobile broadband` option is unchecked before you use Gammu. If this option is enabled you will get permission denied errors from Gammu.

The above procedure does not work with CDMA mobiles.


Develop SMS Gateway with gammu , php, mysql on ubuntu 10.10

Comments (1)

How to bypass Airtel torrents block

I have being using my Airtel Broadband connectivity for our residence mostly for browsing and downloading movies of the torrent sites. But lately, I have noticed that all the torrents sites has been blocked since last Friday. When one try to browse,, you are shown a screen stating “Access to this site has been blocked as per Court Orders”. Damm, how to download, from where to download.

Airtel blocking torrent kickasstorrent site

Solution: Use a secured connection for accessing the sites. Use https instead of http. would work like a charm. Seems like ISP forgot to block those 🙂

Bypass Airtel blocked torrent sites using https

Comments (7)

Technology for the masses (Contd) …

One more instance that I ran into. We had gone out for dinner to Sree Nandhini Palace, which is located in New BEL Road opposite to Beijing Bites, with one of my colleagues. Though I have visited this place many number of times, this was the first time I have noticed them using technology.

WiFi was installed in the whole area. Waiters were carrying iPhones instead of the regular pen and paper to take the orders. They have built in an customize application to run on them to take the orders as well as print them to a network printer near the counter.

Electronic gadgets being part of the common man shows the progress that India has made and about the economic reforms that it have undergone.

Waiter with the iPhone ready to take order

iPhone on the banane leaf

Technology for the masses …

Comments off

Migrating SYBYL

SYBYL is a proprietary product from Tripos. It provides a whole bunch of intuitive molecular modeling for life scientists who are interested in drug and design. You need to buy a copy from them and get the license manager file made or get the license manager file from another user.

Requirements: Migrate an existing instance of SYBYL from one machine to another, using the same license file.

The initial installation of SYBYL was being carried out, by the vendor itself (since it was in support) on RHEL 4, wherein they have done all the installation including support, creating the license etc. But since the machine in which it was installed is no longer functional, we had to urgently shift it to a new machine.

The migration process is as stated below:

1. Got a new machine and installed CentOS 5.6.
2. Created a new user `tripos`, since SYBYL uses are normal user for the installation.
3. Copy the license manager file from the old machine to the new one.
4. Open the license file and check for the name of the machine as well as the mac address. The line would look like this,

SERVER 000f2c3de043

From the above line you can see figure out that the old sever name was `` and the mac address is `00:0f:2c:3d:e0:43`
5. Change the hostname of your new computer using the `hostname` command. You need to be root user while using this command,


6. Change the hardware Ethernet address of your new machine to that of your old one. You need to be the root user while using the following,

ifconfig eth0 hw ether 00:0f:2c:3d:e0:43 up

7. Copied all the 4 CD’s to the installation directory
8. Go inside CD1 and do the following,


9. A GUI will pop up which will show your way to the next steps.
10. Path of the old license file.
11. In case you plan to have the other databases installed go on else click on exit after your basic installation.
12. Read the `ToDoList.txt` inside the `sybyl7.2` directory
13. Start the SYBYL license manager using the following commands,

cd trigo
- Enter: trigo -shell sybyl7.2
- Enter: su (enter root password when prompted)
cd $TA_LICENSE/bin/unix
cp ./ /etc/init.d/
/etc/init.d/ -up

14. Once the license manager is started you can use the sybyl software. The binaries will be kept in sybyl7.2/bin/linux

Note: There might be errors, which might crop up while running sybyl. I have listed some of them,

Error 1: sybyl7.2/bin/linux/autoterm.exe: error while loading shared libraries: cannot open shared object file
Error 2: sybyl7.2/bin/linux/autoterm.exe: error while loading shared libraries: cannot open shared object file
Error 3: sybyl7.2/bin/linux/autoterm.exe: error while loading shared libraries: cannot open shared object file
Error 4: sybyl7.2/bin/linux/autoterm.exe: error while loading shared libraries: wrong ELF class: ELFCLASS64

As part of the solution 1,2 and 3 you need to install the following,

yum install openmotiff22 mesa-libGLU-6.5.1-7.8.el5.i386

Error 4 came up, since I was installing a 32 bit application on a 64 bit machine.

In case you have any more dependencies, you can use the following command,

yum whatprovides library-name

After all the installation is done, you are done good to run sybyl.


Installing VMware Server 2.0.2 on Debian Squeeze

Tested both the 32 bit version as well as the 64 bit version of the VMware server 2.0.2. It seems none of them works out of the box in Debian. One need to apply patches but there are instances wherein even after applying the patches, the server fails to start up. Even the VMware Server forums were clueless about it. There are a lot of if’s and but’s to the solution.

Before starting the installation, you need to install the following packages:
apt-get install build-essential psmisc linux-headers-`uname -r`

Installing the 32 bit version.

1. Download the 32 bit VMware server .tgz file from
2. Extract the .tgz file.
3. Download the patch vmware-sever-2-0-2-32bit.tgz. Change the DIR in accordingly to your location of the VMware Server .tgz file.
4. ./ //vmware-server-distrib/lib/modules/source
5. cd //vmware-server-distrib
6. ./

Installing the 64 bit version.

1. Download the 64 bit VMware server .tgz file from
2. Extract the .tgz file.
3. Download the patch vmware-sever-2-0-2-64bit.tgz. Change the DIR in and the path in accordingly.
4. Patch is applied and the script will start the installation.

There might still be issues with SSL error being shown up. You can try doing the following,

1. mv /usr/lib/vmware/lib/ /usr/lib/vmware/lib/
2. /etc/init.d/vmware restart

Firefox version 3.6 will not show up the management interface. It will show up a blank screen. You need to have version lower then this.


1. VMware Server on 32 bit Debian Squeeze
2. VMware Server on 64 bit Debian Squeeze

Note: Refer to the links mentioned above for more information.

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Open Source Control Panels

In case you are planning to host a server with all the open source software, the below mentioned links might be handy. Normally when you buy a server space/web space you are handed over a interface through which you maintain the various activities of the server, like creating databases, installing applications etc. The panel provided normally is cPanel. cPanel is not free but a proprietary product of cPanel Inc.

So, is there any open source software equivalent of cPanel. Yes, there is.

I myself have tried OpenPanel, which provides me a similar set of features as cPanel. You could very well try the others and install the one which meets your requirements.

Shell based access for your servers hosted outside –

Happy reselling 🙂


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