September 23, 2015
Open VPN Server Configuration on Linux
Linux General,Install Open VPN RPM. Dependencies openssl lzo pkcs11-helper Download openvpn-<version>.rpm , And install using this command rpm -ivh openvpn-<version>.rpm It will create folder under /etc/openvpn and /usr/share/doc/openvpn-2.1.1 cp -r /usr/share/doc/openvpn-<version>/easy-rsa /etc/openvpn cp -r /usr/share/doc/openvpn-<version>/sample-config-files/server.conf /etc/openvpn we have to copy the “easy-rsa” folder and “server.conf” file from /user/share/doc/openvpn-<version>… to…. /etc/openvpn Then go to /etc/openvpn cd /etc/openvpn…
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September 12, 2015
Networking Concepts, in RHEL 7 or CENTOS7.
Linux General,Let’s see the networking concepts, in RHEL 7 or CENTOS7. You should concentrate on these if servers upgrade: We usually edit the network configuration file in the older versions to manage IPs. under /etc/sysconfig/network-scripts/ In the new version no more editing is required. We can add, modify, delete the IPs using the tool called NMCLI…
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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…
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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…
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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…
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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…
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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…
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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…
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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…
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February 10, 2015
Integrating Parallels Virtuozzo container in Citrix Xen server
Linux General,We are trying to install virtuozzo 4.7 in a virtual Machine that has got centos running on it. Virtuozzo installation in this VM goes fine and the VM prompts for reboot post installation. During boot operation, the VM console freezes with lot of errors whereas you can still login to the Virtual machine using putty…
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