CS & IT Solutions

This is my really short installation log of how I installed and configured a DHCP server on Ubuntu Hardy Heron.

1: Make sure that the latest version is installed:

sudo apt-get install dhcp3-server

Note: Don’t be alarmed if the startup fails; that’s because you haven’t configured it yet.

2.1: Edit the DHCP server configuration:

sudo nano /etc/dhcp3/dhcpd.conf

2.2: The contents of my configuration file, for me the comments already in the file was what I needed to make the necessary changes:

# The ddns-updates-style parameter controls whether
# or not the server will
# attempt to do a DNS update when a lease is confirmed.
# We default to the
# behavior of the version 2 packages
# ('none', since DHCP v2 didn't
# have support for DDNS.)
ddns-update-style none;

# option definitions common to all supported networks...
option domain-name "home.lan";
option domain-name-servers ubuntu.home.lan;

default-lease-time 600;
max-lease-time 7200;

# If this DHCP server is the official DHCP server for the local
# network, the authoritative directive should be uncommented.
authoritative;

# This is a very basic subnet declaration.
subnet 10.10.10.0 netmask 255.255.255.0 {
  range 10.10.10.100 10.10.10.200;
  option routers router.home.lan;
}

3: Start the DHCP server (it should now start without problems):

sudo /etc/init.d/dhcp3-server start

Done

Thanks to Author, source http://lani78.wordpress.com/2008/08/10/

setting-up-a-dhcp-server-on-ubuntu-hardy-heron/

Back in September I revived my MiniITX box to serve as a backup server. I set up BackupPC, ran it once, it seemed to work, and then ignored it for weeks. When I checked back, it hadn’t run successfully since. Ugh, I want backups to just work!

A few nights ago I decided to try again, this time dropping the constraint of not installing software on my laptop. Turns out I already had the building block I needed: rsync, installed in the form of Cygwin.

I began with these Rsync for Windows instructions, and everything went smoothly until the very end—rsync on Windows wasn’t connecting to rsync on Ubuntu. My gut told me rsync’s port 873 isn’t open on Ubuntu, but I had no idea how to open ports anymore. Luckily I found How to start rsync daemon at boot in the Ubuntu forums which told me exactly what I needed to know.

Partly as an aide to my memory, and partly to help anyone out there who might be struggling with the same project (unless everyone except me is already backing up their computers) I decided to summarize the process without all the false starts and dead ends it took me to figure it all out. For more information, the rsync man page is useful, as well as the results in Google for windows rsync.

Set up rsync server on Ubuntu

1. Run <font style="background-color: #eeeecc" size="3">sudo apt-get install rsync</font> (it’s probably already installed)
2. Create a file named rsyncd.conf in /etc

   1. sudo nano /etc/rsyncd.conf

   2. Add the following to rsynd.conf, replacing all instances of <strong><font style="background-color: #eeeecc" size="3">username</font></strong> with your Ubuntu username:

      [<strong>username</strong>backup]

   3. path = /home/<strong>username</strong>/backup

   4. comment = Backup     uid = <strong>username</strong>

   5. gid = <strong>username</strong>     read only = false

   6. auth users = <strong>username</strong>

   7. secrets file = /etc/rsyncd.secrets

   8. sudo chmod 644 /etc/rsynd.conf

3. Create a file named rsyncd.secrets in /etc

   1. sudo nano /etc/rsyncd.secrets

   2. Add the following to rsyncd.secrets, replacing <strong><font style="background-color: #eeeecc" size="3">username</font></strong> with your username and <strong><font style="background-color: #eeeecc" size="3">password</font></strong> with a password of your choosing:

      <strong>username</strong>:<strong>password</strong>

   3. sudo chmod 600 /etc/rsyncd.secrets

4. Open rsync port by editing /etc/default/rsync and setting

   RSYNC_ENABLE=true

5. Restart rsync

   sudo /etc/init.d/rsync restart

Set up rsync client on Windows

1. Install Cygwin, making sure Editors > nano and Net > rsync are selected
2. Add <font style="background-color: #eeeecc" size="3">C:\cygwin\bin;</font> to the Windows PATH statement
   1. Right-click on My Computer and select Properties
   2. Switch to the Advanced tab and click the Environment Variables button at the bottom
   3. Find the “Path” or “PATH” variable in the System variables list at the bottom and click Edit
   4. Add <font style="background-color: #eeeecc" size="3">C:\cygwin\bin;</font> to the beginning of the list
3. Create secret file to store password in Cygwin
   1. Start Cygwin Bash Shell
   2. Create secret file in the filesystem root and enter only the password in rsyncd.secrets above, with no spaces or line breaks

      nano /secret

   3. chmod 600 /secret

   4. chown Administrator:SYSTEM /secret

4. Create bat file to run rsync
   1. Open Notepad and enter the following command, replacing User Name with your Windows User Name directory, username with your Ubuntu username, and ipaddress with the IP address of your Ubuntu server (e.g. 192.168.0.100):

One of the most noticeable differences between Linux and Windows is the directory structure. Not only is the format different, but the logic of where to find things is different.

Introduction

In Windows, you use this format to access a directory

D:\Folder\subfolder\file.txt

In Linux, this is the basic format

/Folder/subfolder/file.txt

You’ll notice that the slashes are forward slashes in Linux versus backslashes in Windows. Also, there is no drive name (C:, D:, etc.) in Linux. At boot, the ‘root partition’ is mounted at /. All files, folders, devices and drives are mounted under /. Though it is not apparent from this example, it is important to note that files and folders in Linux are case sensitive.

/Folder/subfolder/file.txt is not the same as /folder/subfolder/file.txt.

Linux Directory Structure Overview

The Directory Structure in Unix & Linux are a unified Directory Structure where in all the directories are unified under the “/” Root file system. Irrespective of where the File System is physically mounted all the directories are arranged hierarchically under the Root file system.

The Linux Directory Structure follows the “Filesystem Hierarchy Structure (FHS)” maintained by the Free Standards Group although most of the distributions sometimes tend to deviate from the standards.

Lets have a quick stroll across the different directories under the Linux Filesystem Hierarchy

“/” Root

The Directory Structure starts with the Root file system “/” and is indeed the root directory for the whole structure.The partition where / (the root directory) will be located on a UNIX or UNIX-compatible system.

/boot

The /boot directory contains the Boot loader files including Grub or Lilo, the Kernel, initrd and system.map config files

/sys

This contains the Kernel, Firmware and system related files.

/sbin

Contains the essential System Binaries and System Administration tools essential for the system operation and performance

/bin

Contains the essential binaries for users and those utilities that are required in single user mode. Examples, include cat, ls, cp etc.

/lib

Contains the library files for all the binaries held in the /sbin & /bin directories

/dev

The /dev directory contains the essential system files and drivers.

/etc

The /etc/directory contain essential System configuration files including /etc/hosts, /etc/resolv.conf, nsswitch.conf, defaults and network configuration files. These are mostly host specific system and application configuration files.

/home

All the user home directories are held under this directory with the exception of the root home directory which is kept under /root directory. This directory holds users files, personal settings like .profile etc.

/media

A generic mount point for removable media like CD-ROM, USB, Floppies etc

/mnt

A generic mount point for temporary file systems. This comes handy particulary when troubleshooting from CDROM etc wherein you might have to mount the Root file system and edit configurations.

/opt

A rarely used directory in Linux for Optional Software Packages. This is extensively used in UNIX OS like Sun Solaris where the software packages are installed

/usr

A sub hierarchy to the root file system which is a User data directory. Contains user specific utilities and applications. You will again see a lot of important but not critical file systems are mounted. Here you would again find a bin, sbin & lib directory which contains non-critical user and system binaries and related libraries and a share directory. Also found here are the include directory with include files

/usr/sbin

Contains Non-essential Non-critical system binaries and network utilities

/usr/bin

Contains Non-Essential Non-critical command binaries for users.

/usr/lib

Library files for the binaries in /usr/bin & /usr/sbin directory.

/usr/share

A platform-independent shared data directory

/usr/local

A sub hierarchy under the /usr directory which has Local System specific data including user and system binaries and their libraries

/var

The /var directory is mostly mounted as a separate filesystem under the root where in all the variable content like logs, spool files for printers, crontab,at jobs, mail, running process, lock files etc. Care has to be taken in planning this file system and maintenance as this can fill up pretty quickly and when the FileSystem is full can cause system and application operational issues.

/tmp

A temporary file system which hold temporary files which are cleared at system reboot. There is also a /var/tmp directory which holds temporary files too. the only difference between the two is that /var/tmp directory holds files that are protected at system reboot. In other words, /var/tmp files are not flushed upon a reboot.

Then you have the virtual (psuedo) file system /proc which resides in the memory and is mounted under the Root holding kernel and process stats in text file formats.

Linux Directory Structure in Visual View

Note:-

This structure could vary from distro to distro and this is a very generic linux directory structure.The directory structure in Linux can be confusing for new users of Linux. Most distributions have the same general structure of the base directory system.

Thanks to Author, source http://www.debianadmin.com/linux-directory-structure-overview.html