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LiNUX ::

UNIX OS


What is UNIX |

UNIX is an operating system which was first developed in the 1960s, and has been under constant development ever since. By operating system, we mean the suite of programs which make the computer work. It is a stable, multi-user, multi-tasking system for servers, desktops and laptops.

UNIX systems also have a graphical user interface (GUI) similar to Microsoft Windows which provides an easy to use environment. However, knowledge of UNIX is required for operations, which aren’t covered by a graphical program, or for when there is no windows interface available, for example, in a telnet session.

Types of UNIX
There are many different versions of UNIX, although they share common similarities. The most popular varieties of UNIX are Sun Solaris, GNU/Linux, and MacOS X. Solaris on our servers and workstations, and Fedora Linux on the servers and desktop PCs.

The UNIX OS
The UNIX operating system is made up of three parts; the kernel, the shell and the programs.

[To be continued]

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Easily you can install Linux UBUNTU ::


Easily you can install Linux UBUNTU

Some PC users think that Linux Operating System Installation step is very critical but not, it is easy.

For this, at first you entry in the BIOS or CE-MOS Select First Boot-able device is CD ROM or DVD-ROM. Then insert UBUNTU Linux CD in the CD/DVD-ROM.

When start your desktop PC, laptop, then you will see the window & select Install UBUNTU, Press enter option of your keyboard.

UBUNTU Installed In Six (6) Step.

  • At First, select language, which language format you want to use. example :  you can select language English.
  • Secondly, select the place; [example Place: Dhaka] & Click Forward Button.
  • Thirdly, select the Layout Of Keyboard & Click Forward Button.
  • Finally, you write The User Full Name & Information.

If your system use in “ Dhaka ” Please write of User Id & Password.

Carefully see, same Password type beside two – address box. Next, you will enter the Next Step By Forward.
This step is more important, so carefully complete everything.

Next, select ” Manually Edit Partition” option & enter Forward Button. Now, your computer system show all disk partition. Now you want to install UBUNTU in your chosen drive, that drive space will be maximum 5 GB. Do Re-size the drive by 5 GB, then create a unallocated space. Again you will be right-click the unallocated space and select the Option “ NEW ”. Now you can select the Linux File System Ent 3. This new drive choice as like “ / ” drive.

Now, you can click on the Rest of Unallocated space and select new option. Again, select the Space, then twice & mention SWAP. Next, you can see the result of all changes & show the drive which want to format.

finally, complete the setup process of UBUNTU Linux, then shut down the PC & start your PC.


FTP Server Configuraion In Linux ReD Hat


Many people using Linux OS Ubuntu.
Sometimes need to make a Server and Configuration Server In Linux Ubuntu OS by RED Hat Inc. (an American multinational software company providing open-source software products to the enterprise community )

FTP :: File Transfer Protocol.

vsFTPd and FTP User Account Configuration:

The vsFTPd ftp server was first made available in Red Hat 9.0. It has been adopted by Suse and OpenBSD as well. This is currently the recommended FTP daemon for use on FTP servers.

Enable vsftpd:

  • Red Hat/Fedora Core/CentOS: VsFTPd is a stand alone service and by the default Fedora Core installation, not controlled by xinetd as is the wu-ftpd default installation.
    Thus start service: service vsftpd start (or: /etc/init.d/vsftpd start)
    Configure vsftpd to start upon system boot: chkconfig --add vsftpd
  • SuSE: By default, the vsftpd is an xinetd controlled service. To enable FTP server services edit the file /etc/xinetd.d/vsftpd and change:
    disable = yes
    to:
    disable = no
    Restart the xinetd daemon: /etc/init.d/xinetd restart
    Note: vsftpd can also be run as a stand-alone service to achieve a faster response time.
  • Ubuntu (dapper6.06) / Debian:
    • Install: apt-get install vsftpd
    • VsFTPd isastand alone service.
      • Start: /etc/init.d/vsftpd start
      • Stop: /etc/init.d/vsftpd stop .

Configuration files:

  • vsFTPdconfiguration file:
    • Fedora Core / Red Hat: /etc/vsftpd/vsftpd.conf
    • S.u.S.e. / Ubuntu (dapper 6.06) / Debian: /etc/vsftpd.conf

Default for Fedora Core 3:

# recommended for security (the code is non-trivial). Not enabling it, may confuse older FTP client.
# async_abor_enable=YES

#ascii_upload_enable=YES        - Improve performance by disabling ASCII mode. Disables command "ascii" and "SIZE /big/file".
#ascii_download_enable=YES

#ftpd_banner=Welcome to YoLinux - Customize the login banner string.

#deny_email_enable=YES          - Disallow specified anonymous e-mail addresses. Used to combat certain DoS attacks.
#banned_email_file=/etc/vsftpd.banned_emails  (default)

#chroot_list_enable=YES         - List users chroot()'d to their home directory. If "NO", list users not chroot()'d.
#chroot_list_file=/etc/vsftpd.chroot_list     (default)

ls_recurse_enable=YES           - Allow "ls -R" recursive directory list. Default is disabled.

pam_service_name=vsftpd

userlist_enable=YES             - (Default) Deny users specified in file /etc/vsftpd.user_list
                                  If "userlist_enable=NO" then allow specified users.
#deny_email_enable=YES          - Disallow specified anonymous e-mail addresses. Used to combat certain DoS attacks.

listen=YES                      - Enable for standalone mode as opposed to an xinetd service.

tcp_wrappers=YES

Restart the FTP service if the config file is changed: service vsftpd restart (or: /etc/init.d/vsftpd restart)

[Potential Pitfall]: vsftp does NOT support comments on the same line as a directive. i.e.:

directive=XXX # comment

  • Specify list of local users chrooted to their home directories: /etc/vsftpd/vsftpd.chroot_list
    (Requires: chroot_list_enable=YES)
            user1
            user2
            ...

user-n

If userlist_enable=NO, then specify users not to be chroot’d..

  • Specify list of users: /etc/vsftpd.user_list
    (Deny list of users requires: userlist_enable=YES)
    Also see PAM configuration below.
root
bin
daemon
adm
lp
sync
shutdown
halt

If userlist_enable=NO, then specify valid users.

  • PAM configuration file Fedora Core 3: /etc/pam.d/vsftpd
#%PAM-1.0
auth       required     pam_listfile.so item=user sense=deny file=/etc/vsftpd.ftpusers onerr=succeed
auth       required     pam_stack.so service=system-auth
auth       required     pam_shells.so
account    required     pam_stack.so service=system-auth

session    required     pam_stack.so service=system-auth

This causes PAM to check /etc/vsftpd.ftpusers for users who are denied. This duplicates /etc/vsftpd.user_list. Speciy user in both files.

File: /etc/vsftpd.ftpusers

root
bin
daemon
adm
lp
sync
shutdown
halt

  • Logrotate configuration file: /etc/logrotate.d/vsftpd.log
/var/log/xferlog {
    # ftpd doesn't handle SIGHUP properly
    nocompress
    missingok

}

 

Sample vsFTPd configurations:

  • Anonymous download FTP server configuration: /etc/vsftpd/vsftpd.conf
# Access rights
anonymous_enable=YES          - Turn on anonymous FTP
chown_uploads=YES             - Uploaded files owned by an assigned user
chown_username=ftp            - Uploaded files owned by this assigned user
local_enable=NO
write_enable=NO               - No upload of files system changes allowed
anon_upload_enable=NO
anon_mkdir_write_enable=NO
anon_other_write_enable=NO
# Security
anon_world_readable_only=YES
connect_from_port_20=YES
force_dot_files=NO
guest_enable=NO
hide_ids=YES
pasv_min_port=50000
pasv_max_port=60000
# Features
xferlog_enable=YES
ls_recurse_enable=NO
ascii_download_enable=NO
async_abor_enable=YES
# Performance
one_process_model=NO
idle_session_timeout=120
data_connection_timeout=300
accept_timeout=60
connect_timeout=60
max_per_ip=4
anon_max_rate=50000

pam_service_name=vsftpd
userlist_enable=YES
#enable for standalone mode
listen=YES

tcp_wrappers=YES

Anonymous logins use the login name “anonymous” and then the user supplies their email address as a password. Any password will be accepted. Used to allow the public to download files from an ftp server. Generally, no upload is permitted.

  • Web hosting configuration: /etc/vsftpd/vsftpd.conf
write_enable=YES                              - Allow users to STOR,  DELE, RNFR, RNTO, MKD, RMD, APPE and SITE
local_umask=022
# Security
connect_from_port_20=YES
force_dot_files=NO
guest_enable=NO                               - Don't remap user name
ftpd_banner=Welcome to Super Duper Hosting    - Customize the login banner string.
chroot_local_user=YES                         - Limit user to browse their own directory only
chroot_list_enable=YES                        - Enable list of system / power users
chroot_list_file=/etc/vsftpd.chroot_list      - Actual list of system / power users
hide_ids=YES
pasv_min_port=50000
pasv_max_port=60000
# Features
xferlog_enable=YES
ls_recurse_enable=NO
ascii_download_enable=NO
async_abor_enable=YES
dirmessage_enable=YES                         - Message greeting held in file .message or specify with message_file=...
# Performance
one_process_model=NO
idle_session_timeout=120
data_connection_timeout=300
accept_timeout=60
connect_timeout=60
max_per_ip=4
#pam_service_name=vsftpd
userlist_enable=YES
#enable for standalone mode
listen=YES

tcp_wrappers=YES

Specify list of local users chrooted to their home directories: /etc/vsftpd/vsftpd.chroot_list
(Requires: chroot_list_enable=YES)

      user1
      user2
      ...

user-n

If userlist_enable=NO, then specify users not to be chroot’d..

. File: .message

A NOTE TO USERS UPLOADING FILES:
   File names may consist of letters (a-z, A-Z), numbers (0-9),
   an under score ("_"), dash ("-") or period (".") only.

The file name may not begin with a period or dash.

 

Test if vsftp is listening: netstat -a | grep ftp

[root]# netstat -a | grep ftp

tcp        0      0 *:ftp                       *:*                         LISTEN