###Squid Proxy Server###
 Features:
  1. Caching server
  2. Filters access to the Net
  3. Efficient bandwidth usage
  4. Supports a wide criteria of ACLs (dstdomain, src_IP, Time of day, etc.)

Tasks:
 1. Install Squid Proxy server
  a. yum -y install squid

/etc/squid - primary configuration container
/etc/squid/squid.conf - primary configuration file
/usr/sbin/squidclient - used to test Squid Proxy server
/var/log/squid - primary log directory
/var/spool/squid - cache directory containter

 2. Start Squid, and ensure that it starts when the system reboots
  a. service squid start
  b. chkconfig --level 35 squid on

Note: Ensure that ample/fast disk storage is available for: /var/spool/squid
Note: Squid defaults to TCP:3128 

 3. Configure Firefox browser to use Squid Proxy server
 
 4. Configure Squid to allow LAN access through, to resources
  a. nano /etc/squid/squid.conf
  b. acl lan_users src 192.168.75.0/24
  c. http_access allow lan_users

 5. Deny 192.168.75.10, but allow ALL other users from the local subnet
  a. 
acl_lan_bad_users src 192.168.75.10
http_access deny acl_lan_bad_users

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Ubuntu 14.04

Linux Mint 17

Python

Nagios

Oracle Linux 7

Reset Root Password

###RAID###
Features:
 1. The ability to increase availability and reliability of data
      (originally redundant array of inexpensive disks; now commonly redundant array of independent disks)
Tasks:
 1. Create a RAID-1 Device (/dev/md0..n)
  a. fdisk /dev/sdb - to create usable raw partitions
  b. partprobe /dev/sdb - to force a kernel update of the partition layout of the      disk: /dev/sdb
  b. mdadm --create /dev/md0 --level=1 --raid-devices=2 /dev/sdb5 /dev/sdb6
  c. cat /proc/mdstat - lists active RAID (md) information
  d. mke2fs -j /dev/md0 - overlays a file system on the RAID device
  e. mount /dev/md0 /raid1
  f. update: /etc/fstab

Note: use 'mdadm --query /dev/md0' to get information about a RAID device

Note: You may create RAID volumes/devices on a single or on multiple disks
Ideally, your RAID volumes should span multiple physical disks to improve:
 a. reliability
 b. performance
 c. availability

 2. Remove the RAID-1 device
 a. umount /dev/md0
 b. mdadm --manage --stop /dev/md0

 3. Create a RAID-5 Volume
 a. fdisk /dev/sdb - to create a partition number 7
 b. partprobe /dev/sdb - to update the kernel's view of the partition table
 c. mdadm --create /dev/md0 --level=5 --raid-devices=3 /dev/sdb5 /dev/sdb6 /dev/sdb7
 d. watch cat /proc/mdstat - refreshes every 2 seconds
 e. Overlay a file system: mke2fs -j /dev/md0
 f. mount /dev/md0 /raid5
 g. Test I/O to RAID-5 device
 h. Update: /etc/fstab

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Fedora 20 in Virtual box

Roboform in linux

Ubuntu server 12.04

Nagios 4.0.7

Oracle Linux 7

Free BSD 10

1. If its local repository then
Install Package createrepo ( this pacakge is present in RHEL 5 dvd in Server folder)

RPM -ivh createrepo

createrepo -v /var/ftp/pub/Server

/var/ftp/pub/Server => this is the directory where local copy of RPM packages are there

Edit the Server.repo file

# vi Server.repo
[Server]
name= redhat
baseurl=file:///var/ftp/pub/Server
[enable=1]
[gpgcheck=0]
Save the file and quit
Then,

#yum clean all
#yum update

Now you can install packages
#yum install package-name

2. If repository is present in server
-----------------------------------------------------------------------------------------------
#cd /etc/yum.repos.d
#ls
Then it will list the files. There is a file with name rhel-debuginfo.repo. Copy this file to a temp file with name Sever.repo. The starting letter of Server should be Capital.
Second step is given below

#cp rhel-debuginfo.repo Server.repo

The Third and final steps
Edit the Server.repo file

# vi Server.repo
[Server]
[name= redhat]
[baseurl=ftp://192.168.0.254/pub/Server] ( eg: IP address : 192.168.0.254 (the server IP)
[enable=1]
[gpgcheck=0]
Save the file and quit
Then,

#yum clean all
#yum update

Now you can install packages
#yum install package-name


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Ubuntu 14.04

Linux Mint 17

Ubuntu Root Password Reset

Lamp in Ubuntu 14.04

Redhat Linux 7 server

Gentoo Linux 12.1

Fedora 20 in Virtual box

Roboform in linux

Ubuntu server 12.04

Nagios 4.0.7

Oracle Linux 7

Free BSD 10

What is Samba ?
Samba can be used to share file and printer between Linux to Linux, Linux to Ubuntu and Linux to Windows.
Daemon  :        smbd, nmbd
Port        :        167,168,169

Features:
 1. Provides Windows features (file & print) on Linux | Unix

/etc/samba/smb.conf - primary config file

Clients:
 1. findsmb - finds SMB hosts on the network
 2. smbtree - equivalent to Network Neighborhood/My Network Places (prints workgroups, hosts, and shares)
 3. smbget - similar to 'wget', in that, it will download files from the remote share
  a. smbget -u dean smb://linuxcbtwin1/mtemp/20070524_SAN_Allocations.ods

 4. smbclient - interactive (FTP-like_ utility to connect to shares - permits uploads/downloads from shares
  a. smbclient -U dean //linuxcbtwin1/mtemp
  b. mget file* - downloads file(s)
  c. mput file* - uploads file(s)


 5. smbtar - backs-up smb shares to a TAR archive
  a. smbtar -s linuxcbtwin1 -x mtemp -u dean -t backup1.tar

Samba Server:
/etc/samba/smb.conf - primary config file

SWAT manages /etc/samba/smb.conf

Samba Server Modes:
 1. User
  a. One Samba-defined user is required per Linux user
  b. Authentication of users is handled by Samba server
 2. Server/Domain (PDC/BDC)
  a. Authentication is handled by the Windows NT/2K/2K3/2K8 server
  b. Still requires a local Samba-defined user accounts database
 3. ADS - Active Directory
  a. Authentication is handled by Active Directory
  b. When used with Winbind, locally-defined Samba users are NOT required

Note: Ultimately, users must authenticate to the local Linux file system

Task:
 1. Install SWAT
  a. yum -y install samba-swat
  b. nano /etc/xinetd.d/swat - set 'disable = no'
  c. service xinetd restart
  d. netstat -ntl | grep 901


/etc/samba/smbpasswd maps Windows users to /etc/passwd

 2. Install rdesktop and connect to Windows XP to test connectivity to Samba
  a. yum -y install rdesktop

Winbind:
 Features:
  1. Windows AD integration
  2. Avoids having to define users in 2 places: Windows, Linux
  3. Uses Kerberos for authentication

Requirements:
 1. krb5-* packages
 2. Properly configured Kerberos environment:
  a. /etc/krb5.conf

[libdefaults]
    default_realm = AD2.LINUXCBT.INTERNAL

[realms]
    AD2.LINUXCBT.INTERNAL = {
        kdc = linuxcbtwin3.ad2.linuxcbt.internal
        admin_server = linuxcbtwin3
    }

[domain_realm]
    .linuxcbtwin3.ad2.linuxbt.internal = AD2.LINUXCBT.INTERNAL


Steps:
 1. Update: /etc/krb5.conf
 2. Update Samba configuration to use ADS authentication
 3. Update Samba server's DNS to point to ADS server
  a. /etc/resolv.conf
  b. /etc/hosts - including a pointer to the ADS server (linuxcbtwin3)

 4. Join AD domain:
  a. 'net ads join -U administrator'
 5. Confirm AD membership using: 'Active Directory Users & Computers' Tool

 6. Setup Winbind to authenticate using ADS:
  a. /etc/pam.d/system-auth - account & auth settings
  auth sufficient /lib/security/pam_winbind.so - place before 'pam_unix.so'
  account sufficient /lib/security/pam_winbind.so

  b. /etc/nsswitch.conf
   passwd: files winbind
   group: files winbind

  c. Configure 'idmap' 'uid & gid' mappings - 10000 - 20000
   Use SWAT to update idmap settings for 'uid & gid'
Note: If you want ADS users to be able to logon to your Samba-Winbind Linux box using SSH, Telnet, mingetty, etc., change the 'Template Shell' directive to a valid shell. i.e. /bin/bash

  d. Create 'Template homedir' %D (Domain) directory beneath '/home'
   mkdir /home/LINUXGENIUS

 7. Test Winbind Integration using: wbinfo
  a. wbinfo -u - this enumerates users in AD
  b. wbinfo -g - this enumerates groups in AD
  c. ssh into LINUXCBTSERV1 (Winbind) as ADS user


Task1:
 1. Authenticate using ADS, as 'administrator' from Windows box
 2. Create a user named 'linuxcbt' in AD
 3. Create shared directory on the Samba box, and provide access (Share it)


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Ubuntu 14.04

Linux Mint 17

Ubuntu Root Password Reset

Lamp in Ubuntu 14.04

Redhat Linux 7 server

Gentoo Linux 12.1

Reset Root Password in linux

Linux Mint 17

pendrive bootable for ubuntu

Nagios 4.0.7

Oracle Linux 7

Fedora 20

###Symlinks###
Features:
 1. Provides shortcuts to files (including directories)
 2. Provides hard links to inode (file system) locations

Soft Links:-
 1. ln -s source_file target
  a. ln -s ./regextest.pl lastscript.pl

Note: Soft links may span multiple file systems/hard drives
Note: Symlink count is NOT increased when using soft links

 2.  ln -s /home/linuxcbt/testRH5/regextest.pl . - this will symlink (soft) to the /boot file system

Note: With soft links, if you change the name or location of the source file, you will break ALL of the symlinks (soft).

Hard Links:-
 Features:
  1. The ability to reference the same inode/hard drive location from multiple   places within the same file system
   a. ln source target
      ln regextest.pl ./testhardregextest.pl - creates a hard link


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