Configuring SNMPv3 client on Red Hat Linux

January 28, 2014
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To configure snmp client version 3 on a Red Hat server you will need to install the packages net-snmp-utils and net-snmp. yum install net-snmp-utils net-snmp Make sure the snmpd service is stopped before you can configure it. service snmpd stop Create a new SNMPv3 user called “andrew”. The authentication password is “auth-pass” using MD5...
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VMware converting RAW disk to VMDK

January 27, 2014
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Convert a Vmware RDM disk to VMDK while guest VM is powered off Power down the guest VM Clone the VM, under select virtual disk format – select Advanced – change the disk format to Thick provisioned. You only need to do this step...
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Add new disk to Red Hat Linux server, create new filesystem without reboot.

January 27, 2014
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If you are running a VMware virtual Red Hat Linux server then it is very easy to add a new disk. For physical servers with hot add capability this is also possible. I am going to show you how to add a new disk...
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Configure the DVD or Linux ISO as software repository for Red Hat Enterprise Linux

September 7, 2012
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You downloaded and installed Red Hat Enterprise Linux on your server becasue you just want to test it out. During installation you selected base server, after installation you realize that you need to install additional packages. But since you did not purchase the Red...
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SSH login without password using public key authentication

August 23, 2012
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On Computer A Create the public and private keys using the command ssh-keygen # ssh-keygen -t rsa Generating public/private rsa key pair. Enter file in which to save the key (/root/.ssh/id_rsa): Enter passphrase (empty for no passphrase): Enter same passphrase again: Your identification...
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Granting Active Directory group privilge to logon to linux server

November 28, 2011
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Likewise similar to Winbind is an open source software used to integrate linux server with Microsoft Active Directory authentication. This article assume that you already have Likewise installed and configured on the Linux server. The steps below is simply to grant a new AD...
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How to shrink a filesystem in Linux

November 28, 2011
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This does not happen often, but you may run into a situation where you need to reduce the size of the Linux filesystem. Well, in my case I wanted to clone my Red Hat Enterprise Linux server which was running in Vmware ESXi. The...
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How to extend the filesystem on a Vmware ESX guest Red Hat Linux server

May 26, 2011
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Being the administrator of a large Linux shop, I have had to extend the filesystems on the Red Hat Linux server a few times. Each time I had the opportunity to extend the filesystem, I found that I struggled to remember the commands and...
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Unable to login to remote server via ssh

May 18, 2011
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A funny thing happened to one of my Red Hat 5 Enterprise servers after applying the errata. I rebooted the servers as usual after applying the updates, and they came up just fine. But unfortunately I was not able to logon remotely via ssh...
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How to create a new superuser in Linux

May 17, 2011
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The administrative account ‘root’ is the most powerful user in Linux and Unix. This account is created by default during installation of the operating system. Most security consultants will recommend that the root account be deleted or renamed. This is to make it harder...
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Troubleshoot problem with yum update and rebuild the rpm database

March 23, 2011
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I have created a step by step approach to troubleshoot a problem with performing yum update and how to rebuild the rpm database. I received and error while trying to update the Redhat Enterprise 5 server kernel using yum update. Looking at the output...
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Booting Red Hat Linux into rescue mode.

January 28, 2011
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Booting Red Hat Linux into rescue mode.

Red Hat Linux can be booted into rescue mode from the installation CD, or any other boot method instead of the system’s hard drive. This also applies to other versions of Linux such as Fedora and Centos. The rescue mode is provided for troubleshooting...
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Identifying the kernel version and changing the default boot kernel in RedHat and Centos Linux.

January 27, 2011
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Use the command uname to print system information in Linux. # uname -r 2.6.18-194.32.1.el5 The –r option will print the kernel release. # uname -s Linux -s prints the kernel name. # uname -n mycomputer.wiivil.com Print the node name or hostname. # uname -p...
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Nslookup resolves address but ping is unable to resolve hostname on Unix server

November 17, 2010
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I came across this issue on my newly built Solaris 10 server. I was able to ping a remote machine by Ip address, but not by its hostname. This indicated that I had the correct route and gateway. Using nslookup and dig I verified...
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How to map to a remote NFS directory from a VMware ESX 4 server.

November 16, 2010
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I ran into this error while trying to mount a NFS directory on a remote server from my Vmware ESX4 server. My Vmware esx server is called esx4-server and the remote NFS server is called remote-server. I executed the mount commant and got the...
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