Category Archives: Uncategorized

>GRE Tunneling with Open Vswitch

Tweet> Tunneling is one of the hot topics in networking. Tunneling create two points in the network and allow traffic to enter on one point and exit on other. No deviation of traffic between these two points, we can say strictly point to point delivery. Tunneling perform encapsulation on the network traffic and forward that via… Read More »

>Using Open vswitch with Fedora 19

Tweet> On my Fedora 19 system, I decided to implement  openvswitch for networking between Host to Guest machine. My guest machine is running on KVM hypervisor.      Openvswitch will here work here as a replacement of linux bridge. Openswitch is implementation of next generation Software Defined Networking(SDN) which manages networking components such as switches(here… Read More »

>Cluster Service Relocation

Tweet> Cluster service relocation takes place automatically when the node running that service goes down.  But sometimes we may need to relocate cluster service from one cluster node to other. For relocating the cluster service we need following information ·         Cluster service name which need to relocated and ·         Node name on which service need… Read More »

>NSS vs OPENSSL

Tweet> We have more than one options for implementation of TLS, SSL and PKCS in Linux. Network Security Services(NSS) and OpenSSL are two common options available in Linux. NSS provides a complete open source implementation of cryptographic libraries. NSS is available both under the Mozilla Public License and GPL . NSS is used by many application… Read More »

>Secure Boot Or hate for Linux?

Tweet>Secure boot is method to boot the operating system by checking the cryptography signature using UEFI(http://en.wikipedia.org/wiki/Unified_Extensible_Firmware_Interface) framework. Secure boot is boot level security which dis allow bypassing signature verification process in booting process. Above explanation of Secure boot sounds good, but what about those users who need dual booting? With the release of Windows 8, Microsoft decided… Read More »

>Debug Kernel Panic

Tweet> Many of you may be already heard about kdump. Kdump is basically a crash debugging mechanism . Kernel Panic is one of such crashing scenario . Suppose , you got in situation where you need crash dump file of kernel panic error . Here I am discussing this in brief . The given below… Read More »

>NFS3 vs NFS4

Tweet> NFS Version 3 added few excellent feature like Asynchronous communication, TCP connection to NFS version 2 . From the security point of view nothing major changed it NFS-3 compare to NFS-2. By default NFS version 3 (Default in RHEL5) use TCP protocol for transport layer communication but UDP protocol use can be forced by… Read More »

>Detect ssh attack using Nagios

Tweet> Recently I noticed some malicious attempt to access my server via ssh . In /var/log/secure , I found following entry+++++++++++++++++++++++Failed password for root from *******+++++++++++++++++++++++++++++++ I decided to get notification for such activities . I thought about two options , one is via syslog-ng mail module and another with Nagios . Since I already… Read More »

>Naglite Installation

Tweet> Let me mention here that this post is only for readers who have exposure in Nagios. Naglite is just a front end viewer for Nagios and mainly used by NOC  for getting better graphical view of down hosts and services . All the Nagios users know that Nagios gives above given interface format to… Read More »

>What happens when a device is plugged in?

Tweet> Many times device Plug-in related questions comes in our mind . These questions specially arises when we face challenges to block certain device on the server , or block certain devices for certain users . Let me explain my understanding on this topic. For newly Plugged-in device , given below steps take place1. Kernel… Read More »