Wednesday, November 1, 2017

A reflection on decision making

Life is a series of decision, some made on impulses while others through serious deliberation.
Perhaps writing down my thought process could help provide clarity when i need it the most.

What works:
Reflecting back on the past, i stood behind every key decision made and this seems to work out well for me. There are no right or wrong decision, your life shapes itself around the decision that you made. If you believe in the decision made, you will inevitably work towards ensuring its success.
Living life with regrets only serves to make one's life worst than it actually is.

What to avoid:
Big decision that has serious implication on yourself and others deserves more time for consideration. Yet time is a precious commodity, and spending too much time could lead to over-thinking and inaction. As such a fine balance is necessary to ensure adequate but not over-thinking.

Approaches:
Listing out the options and its respective pros and cons and question assumption made
Be objective, or try to be
Speak to others
Take your time
Trust your instinct


Thursday, September 28, 2017

Reflection on life

It has been awhile since my last technical posting, a reflection of my current situation as a middle management.

Most technologist in Asia or at least in my narrow perspective could choose to either become an expert in a certain field and risk becoming obsolete or pursue a life trying to scale the corporate ladder.

I have chosen the latter and what it means is a shift in focus from being the problem solver to becoming a shape-shifter taking on the role of a saleman, slave driver, morale booster, leader, prophet, jester.

The role of a manager can be rewarding only if you are given the autonomy to lead your team and that you can produce results. And it is only fair that you should take responsibility of your team's performance.

But often time you will need to do the bidding of higher-ups whose direction you might not always agreed with. So how do you work on something that even you do not believe in ?? It is not impossible, but just very unfulfilling. How do you escape this cycle??

After going through some unfulfilling years at work, i have decided to take a year break from it all. An opportunity to slow down and appreciate life. A quest to do some reflection, to recharge my mind, body and soul (MBS).

As i struggle to define what is MBS, i guess the easiest approach would be to add activities that falls into this category in an iterative manner. The list would be flexible and dynamic but this post will be a good place to note down my commitment.

Mind
Learn something new - (Doing my Masters in information security)
Learn a new language

Body
Exercise - at least twice a week either swim, gym, jog or hike
Sleep - at least 8 hrs
Eat well 

Soul
Practice mindfulness - need to learn that first
Meet new people
Chill 

Wednesday, February 24, 2016

php imap download email to eml a comparison of different approaches

Pieced together a simple php script to download emails using imap.
These are some of the different approaches to download the email as eml format. 
 Approach A   
 $headers = imap_fetchheader($connection, $k, FT_PREFETCHTEXT);  
 $body = imap_body($connection, $k);  
 file_put_contents("pathtoemail.eml", $headers . "\n" . $body);  
 Approach B  
  $body=imap_fetchbody($connection, $k, "");  
 file_put_contents("pathtoemail.eml", $body);  
 Approach C  
  imap_savebody($connection, "pathtoemail.eml", $k);  

Performance comparison when downloading 1 day worth of email. (lower is better)
 Approach A (mins)  
 1. 2.095  
 2. 1.886  
 3. 1.984  
 4. 1.990   
 Approach B (mins)  
 1. 1.447  
 2. 1.357  
 3. 1.399  
 4. 1.413  
 Approach C (mins)  
 1. 1.468  
 2. 1.409  
 3. 1.401  
 4. 1.367  
Conclusion:
Either approach B or C would make a good choice for downloading emails using php imap.
Sample script:
 <?php  
 $time_start = microtime(true);   
 //$server = '{imap.mail.yahoo.com:993/ssl}';  
 $server = '{imap.gmail.com:993/ssl}';  
 //$user = 'xxx@gmail.com';  
 $user = $argv[1];  
 //$pass = 'xxx';  
 $pass = "$argv[2]";  
 date_default_timezone_set('Asia/Shanghai');  
 $criteria = 'SINCE "'.date('d M Y', strtotime('- 1 days')).'"';  
 $connection = imap_open($server, $user, $pass) or die("can't connect: " . imap_last_error());  
 $mailboxes = imap_list($connection, $server, '*');  
 $folder = "./$user/";  
 if(!file_exists($folder)){  
   mkdir($folder, 0777, true);  
 }  
 foreach($mailboxes as $mailbox) {  
   $shortname = str_replace($server, '', $mailbox);  
   echo "$shortname\n";  
   //create folder  
   if(!file_exists("$folder$shortname")){  
     mkdir("$folder$shortname", 0777, true);  
     }  
   //enter into folder  
   imap_reopen($connection, $server.$shortname);  
   $count = imap_num_msg($connection);  
   $uids = imap_search($connection, $criteria, SE_UID, 'UTF-8');  
   if(is_array($uids)){  
     foreach($uids as $ud){    
       $k = imap_msgno ($connection, $ud);  
       //approach A  
       //$headers = imap_fetchheader($connection, $k, FT_PREFETCHTEXT);  
       //$body = imap_body($connection, $k);  
       //file_put_contents("$folder$shortname/$ud.eml", $headers ."\n". $body);  
       //approach B  
       //$body=imap_fetchbody($connection, $k, "");  
       //file_put_contents("$folder$shortname/$ud.eml", $body);  
       //approach C  
       imap_savebody($connection, "$folder$shortname/$ud.eml", $k);  
       echo "saved $ud.eml " . "($count-$k)\n";    
     }  
   }else{  
 //          echo "imap_search failed: " . imap_last_error() . "\n";  
     }  
 }  
   imap_errors();  
   imap_close($connection);  
 $time_end = microtime(true);  
 //dividing with 60 will give the execution time in minutes other wise seconds  
 $execution_time = ($time_end - $time_start)/60;  
 //execution time of the script  
 echo 'Total Execution Time: '.$execution_time.' Mins';  
 ?>  

Friday, September 4, 2015

Starting a VPS reseller business

Just some notes to remind me on how to setup my own VPS services

Pre-requisite:

1 x Server grade dedicated server
Multiple number of IP addresses; 1 for each VPS.
Visualization software:
a) http://solusvm.com/pricing/
b) http://www.virtualizor.com/NOCs

Payment portal
a) WHMCS
b) http://www.docs.modulesgarden.com/SolusVM_Extended_VPS_For_WHMCS

Monday, March 9, 2015

Manually setup Wifi AP with a captive portal on kali linux

As per the topic, this is a post to show how to create a (i) Wifi AP, (ii) redirect users to a captive portal, and (iii) how to allow user to use the internet after they accept the terms and condition on the captive portal.

This is the environment we will be using:
Local interface which is connected to the internet.

1)
interface configuration are located here /etc/network/interfaces
eth0
IP : 192.168.17.28
Mask: 255.255.255.0
GW : 192.168.17.2

Wireless Network
wlan0
IP : 192.168.0.1
Mask: 255.255.255.0
GW : 192.168.0.0

Assuming you already have eth0 setup properly, turn on wireless network interface
 ifconfig wlan0 192.168.0.1  


2)
Configure DHCPD /etc/dhcp/dhcpd.conf
      default-lease-time 300;  
      max-lease-time 360;  
      ddns-update-style none;  
      authoritative;  
      log-facility local7;  
      subnet 192.168.0.0 netmask 255.255.255.0 {  
      range 192.168.0.100 192.168.0.200;  
      option routers 192.168.0.1;  
      option domain-name-servers 192.168.17.2;  
      }  


3)
Enable IP forwarding
 echo "1" > /proc/sys/net/ipv4/ip_forward  


4)
Flush your iptables rules so that we are on the same settings
 iptables -t nat -F  


5)
Configure Iptables to enable traffic masquerading
 iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE   


6)
Configure all Wifi traffic from wlan0 to be redirected to the webserver
 iptables -t nat -A PREROUTING -i wlan0 -p tcp -j DNAT --to-destination 192.168.17.128:80  


7)
Configure your hotspot configuration. HOSTAPD is a utility for creating a AP.
create your configuration file /etc/hostapd/hostapd.conf
# Define interface  
interface=wlan0
driver=nl80211
# Select driver  
ssid=myhotspot
# Set access point name  
hw_mode=g
# Set access point harware mode to 802.11g  
# Enable WPA2 only (1 for WPA, 2 for WPA2, 3 for WPA + WPA2)  
# Set WIFI channel (can be easily changed)  
channel=6
#wpa=2
#wpa_passphrase=mypassword



8)
Time to start DHCPD and hostapd. once started use another device to see if there is a myhotspot.  Everytime you try to surf the internet, you will be redirected to your localhost webserver. Whatever your are serving is called the captive portal.
 dhcpd  
 hostapd /etc/hostapd/hostapd.conf  
 /etc/init.d/apache2 start  


9)
So how do you enable internet for users? One possible way is to use your captive portal to create Iptable rule which enable a particular device (mac address). For example if your device is 11:22:33:11:22:33
 iptables -t nat -I PREROUTING -m mac --mac-source 11:22:33:11:22:33 -j ACCEPT  

Still unclear on step 9? Try looking at pwnstar package.

Having trouble routing ur wifi to ur internet interface ?
https://prahladyeri.wordpress.com/2013/05/26/how-to-turn-your-linux-machine-into-a-wifi-access-point/

Monday, September 29, 2014

Google Scraper

I am in need for analyzing google search result, fortunately there are multiple opensource solution out there. But google hates scrapers and would block your IP should they determine that you are breaking their terms and condition. 

Possible Google Scraper: (Play with the sleep timing between request to prevent IP blocking)
https://github.com/NikolaiT/GoogleScraper
https://github.com/MarioVilas/google


//Example using MarioVilas's google scraper: 
python google.py --stop=20 "inurl:console filetype:php" > test.txt

//If you need to remove parameters, a simple bash script is perfect: 
vi removeparameter.sh
#!/bin/bash
while read p; do
FILE=$p
echo ${FILE%%\?*}
done < test.txt

Tuesday, September 2, 2014

Installing Evilgrade on Centos 6

Installing Evilgrade on Centos gave me abit of problem and took too much time for me thus i am documenting it.

Download Evilgrade from:
https://github.com/infobyte/evilgrade/archive/master.zip

unzip master.zip and go to the directory.

//if you have no error then gd else you will need to install the dependencies
./evilgrade

Required perl dependencies:
Data::Dump
Digest::MD5   
Time::HiRes
RPC::XML
How to install them on Centos using CPAN:
use CPAN, but if you have never used it, then you will need to configure it.

perl -MCPAN -eshell
//step thru the configuration

// key in the below command to automate the configuration
o conf init

cpan -i Data::Dump
cpan -i Digest::MD5
cpan -i Time::HiRes
cpan -i RPC::XML

if you have error with RPC::XML, 
yum whatprovides "perl(XML::Parser)"
yum install ""

yum install perl-IO-Socket-SSL