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SophieDogg

Posts by SophieDogg:

    KVM Clocks and Time Zone Settings

    December 21st, 2011

    So the other day there was an extended power outage down at the dogg pound, and one of my non-essential server racks had to be taken off-line. This particular server rack only has UPS battery backup, but no generator power (like the others), and upon reboot, the clocks in all my QEMU Linux VM’s were wrong! They kept getting set to UTC time instead of local time… After much searching and testing, I finally found out what was necessary to fix this issue. Read More

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    Linux Server Send Email on Boot

    November 22nd, 2011

    It is always nice to have notification of when a server reboots, especially when you are on vacation, away from the office, or just lounging around! In order to send an email on reboot, we can easily create a cron job to run on reboot. Depending on your specific Linux distro, you may encounter some problems with this email going out in a timely manner! Read More

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    Disabling SELinux

    September 9th, 2011

    One of the first things I usually do with most of my servers is disable SELinux. Optimally, you should configure SELinux to allow the services you need, but instead you can just disable the whole darn thing!Read More

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    Creating a new KVM server on a headless machine

    August 30th, 2011

    One of the things any good sysadmin dogg wants to do is setup some virtual servers. Who wants to actually stand in front of a server to do that?! What if the machine is headless (no monitor attached)? Well, as long as we have SSH access to the machine, we can do everything from the dogghouse!Read More

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    Lockd and Statd NFS Errors

    July 30th, 2011

    The other day, the NFS clients at the pound stopped working correctly. Programs that use a NFS share for caching data or locking files (such as Firefox) stopped working without any explanation. My doggs were also unable to compile any programs, which led to a lot of barking and growling from all of them! Read More

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    A Better Linux Firewall

    June 1st, 2011

    Since we recently learned about basic Linux firewalls, I figured that it would be good to cover some more advanced firewall topics. There are a lot of settings that we can use to allow or deny specific traffic from specific hosts. So, let’s jump right in and take a look! Read More

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    Setting up a Linux Firewall

    April 17th, 2011

    One of the first tasks that should be accomplished when deploying a new server (and in reality, any new machine) is setting up a software firewall. On a Linux computer, this is accomplished using iptables. We can use the /sbin/iptables command to manipulate our firewall, or we can directly edit the /etc/sysconfig/iptables file. Each has their advantages, and it’s worthwhile to know how each works.

    Lets start with the iptables command. We can first Read More

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    Configuring SSH on a New Server

    April 12th, 2011

    I recently showed everyone how to install a new CentOS server, and now that we have a running system, we need to do some basic configuration to SSH to make sure our server is secure. When you install your operating system, you should have created an initial root password. We will use this to log in to our system and start configuration.

    One of the first things we need to do is Read More

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    Deploying a New CentOS Server

    April 6th, 2011

    All my doggs keep asking me how to set up a server. I ask them what kind of server, but they never really know. They want to learn Linux, and I want them to too! So I barked to myself, “Why don’t we write up a post to show them how!” Yea! So here I’ll write up how to install a nice new CentOS 5.5 Linux server.

    First, we will need to download the necessary software and Read More

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    No more IPv4!

    April 5th, 2011

    The last available IPv4 addresses have been allocated, which means we all need to start learning about and using IPv6!

    IP addresses are a set of numbers that uniquely identify a host on the internet. IPv4 addresses are composed of four separate 8-bit numbers (for a total of 32 bits), from 0-255, written as 111.222.33.44. As an example, you can run the nslookup command on a domain name, and find the IP address. Many websites have multiple IP addresses, Read More

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