interview question and answer

December 15, 2011

How to configure linux ftp server step by step guide Example and Implementation

ftp server is used to transfer files between server and clients. All major operating system supports ftp. ftp is the most used protocol over internet to transfer files. Like most Internet operations, FTP works on a client/ server model. FTP client programs can enable users to transfer files to and from a remote system running an FTP server program.
Any Linux system can operate as an FTP server. It has to run only the server software—an FTP daemon with the appropriate configuration. Transfers are made between user accounts on client and server systems. A user on the remote system has to log in to an account on a server and can then transfer files to and from that account's directories only.
A special kind of user account, named ftp, allows any user to log in to it with the username “anonymous.” This account has its own set of directories and files that are considered public, available to anyone on the network who wants to download them.
The numerous FTP sites on the Internet are FTP servers supporting FTP user accounts with anonymous login. Any Linux system can be configured to support anonymous FTP access, turning them into network FTP sites. Such sites can work on an intranet or on the Internet.

Configuring the ftp Server

The vsftpd RPM package is required to configure a Red Hat Enterprise Linux system as an ftp server. If it is not already installed, install it with rpm commands as described in our pervious article. After it is installed, start the service as root with the command service vsftpd start . The system is now an ftp server and can accept connections. To configure the server to automatically start the service at boot time, execute the command chkconfig vsftpd on as root. To stop the server, execute the command service vsftpd stop. To verify that the server is running, use the command service vsftpd status.

Configure vsftpd server

In this example we will configure a vsftpd server and will transfer files from client side.
For this example we are using three systems one linux server one linux clients and one windows xp clients. To complete these per quest of ftp server Follow this link
  • A linux server with ip address 192.168.0.254 and hostname Server
  • A linux client with ip address 192.168.0.1 and hostname Client1
  • A window client with ip address 192.168.0.2 and hostname Client2
  • Updated /etc/hosts file on both linux system
  • Running portmap and xinetd services
  • Firewall should be off on server
We have configured all these steps in our pervious article.
We suggest you to review that article before start configuration of ssh server. Once you have completed the necessary steps follow this guide.
Three rpm are required to configure ssh server. vsftpd, portmap, xinetd check them if not found then install
rpm
Now check vsftpd, portmap, xinetd service in system service it should be on

#setup
Select System service from list
[*]portmap
[*]xinetd
[*]vsftpd
Now restart xinetd and portmap and vsftpd service
service restart
service vsftpd restart
To keep on these services after reboot on then via chkconfig command
chkconfig
After reboot verify their status. It must be in running condition
service status
Create a normal user named vinita
useradd
Login for this user on other terminal and create a test file
create file

On Linux client

ping from ftp server and run ftp command and give username and password
user login ftp server
after login you can download files from the specified directories

Most commonly commands used on ftp prompt are


put     To upload files on server
get     To download files from server
mput    To upload all files
mget    To download all files
?       To see all available command on ftp prompts
cd      To change remote directory
lcd     To change local directory
help commands on ftp server

On window clients

Now go on window clients and create a file. copy con command is used to create files on window. To save use CTRL+Z
copy con
Now ping from ftp server and invoke ftp session from server, login from user account and download as well as uploads files
user login on window system

Enable root account for ftp session and set permission on user

By default on vsftpd server root account is disable. You cannot login from root account.
deny root for ftp sessions
Now we will enable root account for ftp session and same time we will disable our normal user vinita to use ftp sessions.
open file /etc/vsftpd/ftpusers . Users whose name are set in this file will not allowed to login from ftp.
vi ftpuser
ftp user
By default this file have an entry for root that why root are not allowed to use ftp. remove root from list and add user vinita
ftp user
Now remove entry form /etc/vsftpd/user_list files. Users whose names are set in this file are also not allowed to login from ftp even they are not prompt for password.

userlist
By default this file have an entry for root that way root is denied form login even not asked for password remove root from list and add user vinita
userlist
After saving change in these files restart the vsftpd service
service vsftpd restart
Now go on client system and login from root this time root will login
root login
Now try to login form user vinita she should not prompt form password also
deny vinita

How to set login banner for ftp server

To set login banner open /etc/vsftpd/vsftpd.conf file and search for this tag
banner
Uncomment this tag and set your banner and save file , and restart the vsftpd service
banner
Go on client system and check banner it will appear before user login

No comments: