Howtos / Articles

Monitoring Compaq or HP Smart Array RAID status on CentOS

This howto will step you through the process of setting up the required software to be able to check the status of a Compaq or HP Smart Array and the attached physical and logical drives on CentOS 6 or RHEL. The required program to be able to talk to the Smart Array is called ‘hpacucli’, which can be found in the ‘HP Service Pack for ProLiant’ package. (Note: Some of the commands below require root privileges.) Obtaining and Installing the…

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Installing lspci on CentOS

The lspci command, which can be found in the pciutils package, is a great tool for finding information on the devices in your PC. the lspci command will allow you to get the model number/chip details for devices such as network interface cards, sound cards, raid cards, etc. To install pciutils on CentOS/RHEL using yum: (make sure you are logged in with root privileges) # yum install pciutils Example installation output: # yum install pciutils Loaded plugins: fastestmirror, presto Loading…

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Changing network interface numbers on Ubuntu

Have you ever replaced a network card on Ubuntu and found that it is now appearing as eth1, instead of eth0? Or simply wanted to swap the numbering of two network interfaces? This guide shows you how to do just that. Ubuntu uses the udev dynamic device management system, and automatically keeps track of what net card is assigned to what interface name. Udev allows for device name persistance using rule files, which are stored in “/etc/udev/rules.d/”. “70-persistent-net.rules” is the…

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Monitor your network for new hosts using arpwatch

For computers to communicate with each other over a network, they need to be able to know how to convert a IP address, into the physical address of the network card (MAC address). If your computer doesn’t have the MAC address for the specific host you are trying to communicate with, your computer will send out a broadcast ARP request, to find out who owns the IP you are trying to contact. These ARP requests are broadcast out over a…

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Remove mail from the Postfix queue

Queue maintenance is an important part of the administration of any SMTP mail server. There may be times where you get a lot of emails attempting to be sent, that either aren’t getting transmitted successfully, or you don’t want them to get transmitted. The “postsuper” command allows you to remove individual emails, or even all emails from the queue. If you would like to just remove one specific email from the queue, you need to get the Queue ID. You…

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