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TCP Wrappers

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The TCP Wrappers package (tcp_wrappers) is installed by default and provides host-based access control to network services. The most important component within the package is the /usr/lib/libwrap.a library. In general terms, a TCP-wrapped service is one that has been compiled against the libwrap.a library.

When a connection attempt is made to a TCP-wrapped service, the service first references the host's access files (/etc/hosts.allow and /etc/hosts.deny) to determine whether or not the client is allowed to connect. In most cases, it then uses the syslog daemon (syslogd) to write the name of the requesting client and the requested service to /var/log/secure or /var/log/messages.

Last Updated on Friday, 11 June 2010 10:34

How to Setup VPN using PPTP in CentOS

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The Point-to-Point Tunneling Protocol (PPTP) is a method for implementing virtual private networks (VPN).

Apart from security, a PPTP VPN allows you to use a static ip address of your server for all your internet connection. A great way to get static ip if you are on an ISP that only provides dynamic ip to clients.As Windows XP, Windows VISTA, Windows 7, comes with a built-in PPTP Client, PPTP is the easiest way to use VPN without the requirement for any software installation.

Last Updated on Friday, 11 June 2010 04:34

How to Disable IPv6 Networking?

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Question: Our policy and network configuration does not requires IPv6 support in RHEL / CentOS / Fedora Linux. How do I prevent the kernel module from loading at boot time and disable IPv6 networking?
You can easily prevent the kernel module from loading by updating the following two files:

1. /etc/modprobe.conf - Kernel driver configuration file.
2. /etc/sysconfig/network - RHEL / CentOS networking configuration file.

Last Updated on Thursday, 10 June 2010 06:02

Bandwidth Monitoring with NTop (Network Top)

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NTop is a network traffic probe that shows the network usage, similar to what the popular top Unix command does. ntop is based on libpcap and it has been written in a portable way in order to virtually run on every Unix platform and on Win32 as well.

NTop users can use a a web browser (e.g. firefox, netscape) to navigate through ntop (that acts as a web server) traffic information and get a dump of the network status. In the latter case, ntop can be seen as a simple RMON-like agent with an embedded web interface.

Last Updated on Thursday, 10 June 2010 06:04

How to Yum local repo in Centos using ISO file

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  • CentOS 5.2
  • Intermediate knowledge of Linux
  • NFS


it is very important to save your precious bandwidth during update process because it is not ideal to update every individual system from web and same kind of packages will be downloaded again & again we can do this by downloading latest centos dvd iso & using this dvd as local repo.

Last Updated on Thursday, 10 June 2010 06:04

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