Sunday, 6 April 2014

FTP Server Installation Steps in Linux

What is VSFTPD?

FTP by itself is not a very secure. Data transmitted in clear text, without encryption so making it subject to interception and theft. Now we have more secure options the Very Secure FTP daemon (vsftpd)

VSFTPD features

  • Virtual IP configurations
  • Powerful per-user configurability
  • Band Width limits
  • Per-source-IP configurability
  • Per-source-IP limits
  • IPv6 compatible
  • Encryption support through SSL integration
  • Very high security requirements
  • Good scalability
  • Virtual users can be created
  • Better than average performance
  • High speed

Wednesday, 2 April 2014

FTP server Basics and Types

What is FTP

FTP stands for File Transfer Protocol and it is used as one of the most common means of copying files between server and client over a TCP based network like Internet. FTP is the most used protocol over internet to transfer files.

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.

FTP Ports

FTP uses TCP ports for communication between client and server. It uses two ports Control and Data

FTP Control Channel, TCP Port 21: This port is used for commands that we send and then get back the response from ftp server. It is called control channel and uses port 21.

FTP Data Channel, TCP Port 20: This port is used for the data transfers between the client and server.

Saturday, 15 March 2014

Internal and External Commands in Linux UNIX

Internal Command

Internal commands are the commands that are executed directly by the shell. These commands will not have a separate process. You can’t find these commands in PATH directories in system because these are built in shell command. echo is an external command and if you try to find its path it will show shell built in.

$ type echo
echo is a shell builtin

when you run echo the system will not search in PATH location, it will execute it from shell builtin commands that are stored in some separate file.

Thursday, 13 March 2014

Name Resolver Configuration (resolv.conf) in Linux

Name Resolver

The name resolver is used to convert a human friendly name (hostname) to machine friendly name i.e. (IP address). It is use to configure client side access to the Internet Domain Name System (DNS). This file defines which name servers to use.

Fully Qualified Domain Name

A fully qualified domain name (FQDN) is the complete domain name for a specific computer or host on the Internet. The FQDN consists of two parts: the hostname and the domain name.
The following are examples of FQDNs:

Here .com is the top-level domain (TLD). This is similar to the root directory, from which all other directories originate. is the FQDN of the web server. Here www is the hostname and is domain name.

Tuesday, 11 March 2014

Network Interface Configuration (ifconfig) in Linux

ifconfig command

The “ifconfig” or interface configuration command is used for displaying and configuring the network configuration information like ip address, broadcast address, netmask etc.

ifconfig is used to configure the system's kernel-resident network interfaces. It is used at boot time to set up interfaces as necessary. After that, it is usually only needed when debugging or when system tuning is needed.