August 26, 2015
Symbolic link hack and its prevention in cPanel based servers.
Linux General,Symbolic link: Just like we use shortcut in windows based operating system. Symbolic link (symlink or soft link) is a shortcut like file in linux operating systems. In linux a normal user cannot access server main/root directory. So, they use this symlink option as a tool to hack/gain access to server main/root directory. User will…
Read more
August 14, 2015
DNS Configuration (Internal and External)
Linux General,The following package must be installed : bind-9.8.2-0.17.rc1.el6_4.6.i686.rpm bind-chroot-9.8.2-0.17.rc1.el6_4.6.i686.rpm bind-utils-9.8.2-0.17.rc1.el6_4.6.i686.rpm bind-libs-9.8.2-0.17.rc1.el6_4.6.i686.rpm Install DNS: Install bind and bind-chroot package using bellow command rpm -ivh bind-9.8.2-0.17.rc1.el6_4.6.i686.rpm rpm -ivh bind-chroot-9.8.2-0.17.rc1.el6_4.6.i686.rpm rpm -ivh bind-utils-9.8.2-0.17.rc1.el6_4.6.i686.rpm rpm -ivh bind-libs-9.8.2-0.17.rc1.el6_4.6.i686.rpm Create DNS key using below format: % dnssec-keygen -a hmac-md5 -b 128 -n USER dhcpupdate Kdhcpupdate.+157+14638 This will create a 128bit…
Read more
July 13, 2015
Routing Basics
Network,Routers in a network discover remote networks in two ways Statically configured routes Dynamic routing protocols By default routers knows only the directly connected networks represented by “C” Static Routing Static route are mainly used when routing from a particular network to a stub network. Stub networks are the networks that can be accessed through…
Read more
July 8, 2015
Routers Basics
Network,ROUTERS: It is an internetworking component that connects networks at different geographical locations.It has Serial Port Auxillary Port Console Port AUI (Attachment Unit Interface) or Ethernet(which uses RJ45 port) Routers are of two types Fixed -fixed number of slots (series from 700 to 2500, exception 1750, 1751) Modular – Upgradable slots and ports (series from…
Read more
July 1, 2015
Networking Basics
Network,What is a Network? A network is any collection of independent computers(devices) which are connected to one another to share files and peripherals such as printers, modems, tape drives. Every Network includes: At least two computer server or client work station Network Interface card(NIC) A connection medium(wired or wireless) Network Operating System software Protocols: Protocols…
Read more
June 18, 2015
Iperf
Linux General,Iperf was developed by NLANR/DAST as a modern alternative for measuring maximum TCP and UDP bandwidth performance. Iperf allows the tuning of various parameters and UDP characteristics. Iperf reports bandwidth, delay jitter, datagram loss. Iperf is available also for Windows The quality of a link can be tested as follows: – Latency (response time or…
Read more
June 2, 2015
MySQLTuner-perl Script
Linux General,MySQLTuner is a script written in Perl that allows you to review a MySQL installation quickly and make adjustments to increase performance and stability. The current configuration variables and status data is retrieved and presented in a brief format along with some basic performance suggestions. Compatibility: MySQL 3.23, 4.0, 4.1, 5.0, 5.1 (full support) MySQL…
Read more
May 25, 2015
Linux – Creating a Partition Size Larger Than 2TB using Parted Command
Linux General,Find Out Current Disk Size: fdisk -l /dev/sdb Disk /dev/sdb: 3000.6 GB, 3000592982016 bytes 255 heads, 63 sectors/track, 364801 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Disk /dev/sdb doesn’t contain a valid…
Read more
May 12, 2015
Add multiple interface and IP address – ubuntu and centos
Linux General,The below script uses to add bulk IPs for the same gateway and subnet : Save IPs in a file like /opt/dummy.txt and run the script to add them up. Interface add script – Ubuntu or Centos: echo Enter Distribution ubuntu\/centos read os if [ “$os” == “centos” ] then echo Enter Interface Name read…
Read more
April 30, 2015
MEGACLI Commands to check Hardware RAID config and Setup
Linux General,To know the Hardware RAID controller and other information use the lspci command. lspci | grep -i raid O/P: 01:00.0 RAID bus controller: LSI Logic / Symbios Logic MegaRAID SAS 2108 [Liberator] (rev 05) The above command shows the RAID controller vendor details. Installation of Megacli in Centos: Download the MeGaCLIzip from the below link:http://www.lsi.com/downloads/Public/RAID…
Read more
