need to know today

How to call an class with arguments from another class in ruby or puppet DSL ???

CHEF post 1

Hi all

I am started to learning CHEF,  you may thought i am going to cook some food. ha  ha ha, very funny guys. Those who doesn't know what is chef, It is an configuration management language. so you think, some of us using some other tools are scripts to manage config files. CHEF is an new concept , it's been there for many years, i am started learning now, i am going to do an walkthrough for my CHEF knowledge with all of you ..!!!

Thanks
Thirumoorthi

What I learned Today " Password less login for your servers "

Hi all ,

Even though some of the servers are  compromised using passwords , So to avoid those kind of issues we have to setup Password less login to ensure high safety and security to our servers.

Steps : Create SSH keys to your user id in your server , use bellow commands to create SSH keys ,

cd ~/.ssh
ssh-keygen -t dsa -b 1024

Create an PEM key from an gerenated PRIVATEKEY

openssl dsa -in id_dsa -outform pem > test.pem 

Copy generated Public key to Authorized_keys file,

cat id_dsa.pub >> authorized_keys

That's it we are done with the key generation. We have to do is to copy that pem key to 

local machine and log in to  that server with this pem key.

ssh -i "test.pem" username@servername 

That's it we are good to gooooo.....!!!!!

Completed first python script on Excel automation

I am happy to share that I finished excel  automation for my official work.I actually used openpyxl for my xlsx automation. I feel great when I done it. Before that I thought automating an excellent work is bit difficult but  once you learn to do, it's mind blowing.

I'm trying to automate xlsx works for an little bit of an time. But due to some backlogs I didn't finish it on the expected time period. 

test post for my tweet

Test

What I learned today sep 30th 2015

I find out that search and replace for an file using SED editor

sed -i 's#055#007#' /etc/login.defs ; grep UMASK /etc/login.defs

above command replaces 055 value in login.defs to 007,
this may looks like simple, but it is more powerfull stuff

what i learned #today 20-07-2015

Hi all ,

one of my friend asked me how to scan newly  attached LUN's

How to scan new FC LUNS and SCSI disks in Linux ?

How to scan new FC LUNS and  SCSI disks in Redhat Linux without rebooting the server?  Most of the Linux beginners have wondering how to do this and this article will be for them.It may look like very simple as we perform this in daily operation to scan luns but system has many work to do in background when you execute storage scanning commands. Redhat says this type of scan can be distributive,since it can cause delays while I/O operation timeout and remove devices unexpectedly from OS.So perform this scan when really you want to scan the disks and LUNS.

Scanning FC-LUN’s in Redhat Linux

1.First find out how many disks are visible in “fdisk -l” .

# fdisk -l 2>/dev/null | egrep '^Disk' | egrep -v 'dm-' | wc -l 

2.Find out how many host bus adapter configured in the Linux box.you can use “systool -fc_host -v” to verify available FC in the system.

# ls /sys/class/fc_host
host0  host1  

In this case,you need to scan host0 & host1 HBA.

3.If the system virtual memory is too low ,then do not proceed further.If you have enough free virtual memory,then you can proceed with below command to scan new LUNS.

# echo "1" > /sys/class/fc_host/host0/issue_lip
# echo "1" > /sys/class/fc_host/host1/issue_lip

Note: You need to monitor the “issue_lip” in /var/log/messages to determine when the scan will complete.This operation is an asynchronous operation.

4.Verify if the new LUN is visible or not by counting the available disks.

# fdisk -l 2>/dev/null | egrep '^Disk' | egrep -v 'dm-' | wc -l 

If any new LUNS added ,then you can see more count is more then before scanning the LUNS.

Scanning SCSI DISKS in Redhat Linux

1.Finding the existing disk from fdisk.

[root@mylinz1 ~]# fdisk -l |egrep '^Disk' |egrep -v 'dm-'
Disk /dev/sda: 21.5 GB, 21474836480 bytes

2.Find out how many SCSI controller configured.

[root@mylinz1 ~]# ls /sys/class/scsi_host/host
host0 host1 host2

In this case,you need to scan host0,host1 & host2.

3.Scan the SCSI disks using below command.

[root@mylinz1 ~]# echo "- - -" > /sys/class/scsi_host/host0/scan
[root@mylinz1 ~]# echo "- - -" > /sys/class/scsi_host/host1/scan
[root@mylinz1 ~]# echo "- - -" > /sys/class/scsi_host/host2/scan

4.Verify if the new disks are visible or not.

[root@mylinz1 ~]# fdisk -l |egrep '^Disk' |egrep -v 'dm-'
Disk /dev/sda: 21.5 GB, 21474836480 bytes
Disk /dev/sdb: 1073 MB, 1073741824 bytes
Disk /dev/sdc: 1073 MB, 1073741824 bytes

From Redhat Linux 5.4 onwards, redhat introduced “/usr/bin/rescan-scsi-bus.sh” script to scan all the SCSI bus and update the SCSI layer to reflect new devices. 

But most of the time,script will not be able to scan new disks and you need go with echo command.

please look into this link 

Thank you for reading this article.

What i learned today 15-07-2015

Today we have some problem faced in our environment, that we have to check whether the LDAP port is opened or closed . usually  we go with telnet command that will show us which port is opened.

But  some times we should to check more than that , so we should use tcpdump to check on all the details as required.

following is the command used to solve 

tcpdump -i ethernetnumber port 909

 eg :- tcpdump -i eth0 port 909

Above example gives you whats going  on in particular port 909.

What i learned today 9-7-15

Hi all

Bellow are the things learned today.

1.

I understand why we use blacklist=e1000e command in kernel arguments while installing OS in physical servers, i do this previously in server os installations but i forget it some how.

guys please make an note of this, because it is really helpfull for you while installing OS. problem is anaconda installer  is unable to find which network card to be used to search for rpms to proceed with OS installation.

2.

for the first time in my life i used for loop in my work environment , wow it works amazing(i know) , But when you feel an relaxation while it creates output as you desired.
     I look for ways to bringing up all the network cards in my network , usualy what we do means that we go and enter all the cards one by one , we know there is an option for it to reduce the process but we are not ready to find out how to solve it , i just googled it and find out these.

     for i in {0..15};do ifconfig eth"$i" up ; done

This looks like simple to you, but it bring up all the network cards in my Server, Pretty weird right. ya i too accept that fact

Reset ADS/LDAP user from client end

Normaly we think if an ADS/LDAP user unable to login means , the problem is with ADS/LDAP server , Guess what it is not




Login counter is an just  an counter it counts number of logins failed it think, if we reset that counter to zero means we can able to login to the server via  that user

you may see following error in /var/log/messages

Jun 10 13:52:04 systemname lsass: [lsass] Failed to authenticate user (name = 'username') -> error = 40056, symbol = LW_ERROR_ACCOUNT_DISABLED, client pid = 31405
Jun 10 13:52:06 systemname sshd[31405]: Failed password for username from x.x.x.x port 1190 ssh2


If you’re root but is not managing to become a user with su, you also need to reset the login counter:



root@testsrv~ # su – username 
su: incorrect password

root@testsrv:~ # /sbin/pam_tally --user user1--reset
User user1 (672) had 34
(or)
 
root@testsrv:~ # /sbin/pam_tally2 --user user1--reset

root@testsrv:~ # su – username
user1@testsrv:~ $

What i know today %date 15th may 2015

1. If you want to rename an file with host name of an server, just do an simple command 

        #mv oldfilename newfilename$(hostname)

instead of host name you can  change it to any variable name 


2. compare two files using following command
           
             # sdiff -s  file1 file2

Default port numbers

Port Number	Description
1	TCP Port Service Multiplexer (TCPMUX)
5	Remote Job Entry (RJE)
7	ECHO
18	Message Send Protocol (MSP)
20	FTP -- Data
21	FTP -- Control
22	SSH Remote Login Protocol
23	Telnet
25	Simple Mail Transfer Protocol (SMTP)
29	MSG ICP
37	Time
42	Host Name Server (Nameserv)
43	WhoIs
49	Login Host Protocol (Login)
53	Domain Name System (DNS)
69	Trivial File Transfer Protocol (TFTP)
70	Gopher Services
79	Finger
80	HTTP
103	X.400 Standard
108	SNA Gateway Access Server
109	POP2
110	POP3
115	Simple File Transfer Protocol (SFTP)
118	SQL Services
119	Newsgroup (NNTP)
137	NetBIOS Name Service
139	NetBIOS Datagram Service
143	Interim Mail Access Protocol (IMAP)
150	NetBIOS Session Service
156	SQL Server
161	SNMP
179	Border Gateway Protocol (BGP)
190	Gateway Access Control Protocol (GACP)
194	Internet Relay Chat (IRC)
197	Directory Location Service (DLS)
389	Lightweight Directory Access Protocol (LDAP)
396	Novell Netware over IP
443	HTTPS
444	Simple Network Paging Protocol (SNPP)
445	Microsoft-DS
458	Apple QuickTime
546	DHCP Client
547	DHCP Server
563	SNEWS
569	MSN
1080	Socks

How to enforce password complexity on Linux

On most Linux systems, you can use PAM (the "pluggable authentication module") to enforce password complexity. If you have a file named /etc/pam.d/system-auth on RedHat (/etc/pam.d/common-password on Debian systems), look for lines that look like those shown below.

$ grep password /etc/pam.d/system-auth
password    requisite     pam_cracklib.so try_first_pass retry=3
password    sufficient    pam_unix.so md5 shadow nullok try_first_pass use_authtok
password    required      pam_deny.so

That's what you should expect to see on a new system.

By default, passwords must have at least six characters (see /etc/login.defs for possible changes). This is hardly long enough by current standards to consider passwords to be secure. You will have a much stronger password complexity policy if you change the first line to something like this, requiring longer passwords and ensuring a degree of complexity as well.

password requisite pam_cracklib.so try_first_pass retry=3 minlength=12 lcredit=1
ucredit=1 dcredit=1 ocredit=1 difok=4

Here's what each of the available parameters does:

try_first_pass = sets the number of times users can attempt setting a good
  password before the passwd command aborts
minlen = establishes a measure of complexity related to the password length
  (more in a moment on this)
lcredit = sets the minimum number of required lowercase letters
ucredit = sets the minimum number of required uppercase letters
dcredit = sets the minimum number of required digits
ocredit = sets the minimum number of required other characters
difok = sets the number of characters that must be different from those in the
   previous password

That said, minlen is actually a measure of complexity, not simply length. It specifies a complexity score that must be reached for a password to be deemed as acceptable. If each character in a password added one to the complexity count, then minlen would simply represent the password length but, if some characters count more than once, the calculation is more complex. So let's see how this works.

The minlen complexity measure is calculated in a number of steps:

• every character in a password yields one point, regardless of the type of character
• every lowercase letter adds one point, but only up to the value of lcredit
• every uppercase letter adds one point, but only up to the value of ucredit
• every digit adds one point, but only up to the value of dcredit
• every special character adds one point, but only up to the value of ocredit

If lcredit, ucredit, dcredit and ocredit were all set to 0, only the password length would be used to determine if it's acceptable. No characters would add extra points to the complexity score.

When you set any of the lcredit, ucredit, dcredit or ocredit parameters to a negative number, then you MUST have at least that number of characters for each character class for the password to pass the complexity test.

Setting minlen to 12 and difok to 4 are generally good settings. However, if you want to require 12 character passwords and complexity too, you will need a larger minlen setting. With minlen set to 12 and one point given for including each of a lowercase, uppercase, digit and special character (the defaults), you could get by with passwords that have only eight characters -- even with minlen set to 12! A stronger policy would be required by this:

password requisite pam_cracklib.so try_first_pass retry=3 minlength=16
lcredit=-1 ucredit=-1 dcredit=-1 ocredit=-1 difok=4

These settings would ensure that your passwords have 12 characters, including at least one characters in each of the four classes.

If you'd like to experiment with the password length and complexity settings, try the script below. It's a bit cumbersome, but it should capture all the requirements aside from the difok(differences) criteria. Change the settings in the first section to match those you want to evaluate.

#!/usr/bin/perl -w

# -- set your complexity preferences here --
$minlen=16;
$lcredit=-1;
$ucredit=-1;
$dcredit=-1;
$ocredit=-1;

# -- initialize the counters --
$score=0;
$lcase=0;
$ucase=0;
$digits=0;
$other=0;

# -- set fail to false --
$fail=0;

# -- check for argument --
if ( $#ARGV < 0 ) {
    print "argument expected\n";
    exit;
} else {
    $password=$ARGV[0];
}

# -- determine if any character settings are mandatory (if negative)
if ($lcredit < 0) {             # needed # of lowercase characters
    $lneeded=-1 * $lcredit;
    $lextra=$lneeded;
} else {
    $lneeded=0;
    $lextra=$lcredit;
}
if ($ucredit < 0) {             # needed # of uppercase characters
    $uneeded=-1 * $ucredit;
    $uextra=$uneeded;
} else {
    $uneeded=0;
    $uextra=$ucredit;
}
if ($dcredit < 0) {             # needed # of digits
    $dneeded=-1 * $dcredit;
    $dextra=$dneeded;
} else {
    $dneeded=0;
    $dextra=$dcredit;
}
if ($ocredit < 0) {             # needed # of special characters
    $oneeded=-1 * $ocredit;
    $oextra=$oneeded;
} else {
    $oneeded=0;
    $oextra=$ocredit;
}

$score=length($password);               # 1 point for each character

# -- count the characters of each type --
foreach $char (split //, $password) {

    if ($char =~ /\d/) {
        $digits++;                      # digits
    } elsif ($char !~ /\w/) {
        $other++;                       # special characters
    } elsif ($char eq lc($char)) {
        $lcase++;                       # lowercase
    } elsif ($char eq uc($char)) {
        $ucase++;                       # uppercase
    } else {
        print "Error: unrecognized character. Please fix this script!\n";
    }
}

if ($lcase < $lneeded) {
    print "password failure: need $lneeded lowercase character(s)\n";
    $fail=1;
}
if ($ucase < $uneeded) {
    print "password failure: need $uneeded uppercase character(s)\n";
    $fail=1;
}
if ($digits < $dneeded) {
    print "password failure: need $dneeded digit(s)\n";
    $fail=1;
}
if ($other < $oneeded) {
    print "password failure: need $oneeded special character(s)\n";
    $fail=1;
}
if ($fail > 0) {
    exit;
}

# -- reduce credits to number allowed --
if ($lcase > $lextra) {
    $lcase=$lextra;
}
if ($ucase > $uextra) {
    $ucase=$uextra;
}
if ($digits > $dextra) {
    $digits=$dextra;
}
if ($other > $oextra) {
    $other=$oextra;
}

print "$score + $lcase + $ucase + $digits + $other\n";
$score=$score + $lcase + $ucase + $digits + $other;

if ($score >= $minlen) {
    print "password passes with score of $score\n";
} else {
    print "password fails with score of $score\n";
}

Check out /etc/login.defs for password expiration parameters -- another component of good password security.

And please note that cracklib ensures that users can't just reverse their prior passwords or rotate letters to avoid making significant password changes. So, p4ssw0rd cannot be replaced with dr0wss4p or 4ssw0rdp.

Creating a app specifically for locating temples, churchs and mosques

The idea behid this is when you are going to a different town in which you don't what is nearby, so we enable this app to solve those kind of situations.
But I think google apps already have this feature but I want to create it different from that..!

Configuring Outlook Express via PowerShell

I don't think there is an option for configuring outlook via power shell , i have to check it out 

Create Filters in Outlook Express

Outlook Express allows you to set up very elaborate filters for handling mail which you can direct to certain folders by setting up Mail Rules.

Outlook Express uses the term Rules, but a Rule and a Filter are the same thing.

• Click on the Tools menu
• Select Message Rules
• Click Mail
• In the Mail Rules window click New

In the New Mail Rule window you will need to follow steps 1 through 4.

• Under the first section, 1. Select the conditions for your rule
• Select which conditions you want to use as the basis of this filter. Choose Where the Subject line contains specific words to block all messages with “[SPAM” in the Subject field, so that all messages tagged by the anti-spam system will be moved to a SPAMBOX folder that you will create later.
• In the second box, 2. Select the Action for your rule
• Check the box Move it to the specified folder
  In each section you can check one or more boxes, depending on what you are trying to accomplish
  As you are checking off your criteria, you will notice that blue keywords will pop up in box 3. Rule Description
• Click the blue keywords to enter your specific criteria for the rule
  You can enter multiple keywords in the same rule
• Enter each keyword or phrase and click Add
  For this rule, just enter SPAM, in all caps
• Click OK to return to the New Mail Rule window
• Under 2. Select the Actions for you Rule, put a check in the box Move it to the Specified folder
• Click the blue keywords in box #3 to change specified folder to SPAMBOX
  You will probably have to create a new folder, or you can use any of your existing folders
• Give your rule a Name
• Click OK

what happens when ur eyebrows tickles

i am not an astrologer or an scientist but my grand mother says that if your right eyebrow tickles means some good thing is going to happen but for an instance if your left eye brow tickles means that you are getting into an fight better you control your tough...,

may people don't believe in karma and all but as an tamilan i believe in my self and karma,

better check this out and comment

YUM COMPLETE CONFIGURATION WITH VIDEO

Yum is a yellow dog update manager it is a new package manager introduced by redhat with RHEL5 in year 2007 but now in RHEL6 they also have this facility to manage the packages. By using YUM we can manage the packages in many ways. YUM is always working in Server /Client environment. To configure YUM Server and Client perform the steps given below

STEP 1 # mount /dev/dvd /mnt

mounting RHEL6 DVD TO AN LOCAL FOLDER 

# cd /mnt/Packages

# rpm -ivh vsftpd

NOTE : Because YUM only can be configured either by using FTP or HTTP

# rpm -ivh createrepo

NOTE : There will be two dependencies just install them

#cd ..

# cp -rfv * /var/ftp/pub

This will start copy of dvd data into the /var/ftp/pub

# cd

# umount  /mnt

# cd /var/ftp/pub

# createrepo -v Packages

NOTE: This will create the private repository of our database

12 Reasons Why Every Linux System Administrator Should be Lazy

12 Reasons Why Every Linux System Administrator Should be Lazy

Tech News - 5 Clever Ways to Get a Job Using Social Media | Techgig

Tech News - 5 Clever Ways to Get a Job Using Social Media | Techgig