Increase CentOS 7’s MTU

Ethernet interfaces normally use an MTU of 1500 bytes. I recently needed to increase the MTU use by the NICs on a point-to-point link to 9000 bytes in order to improve DRBD performance. This is sometimes referred to as enabling jumbo frames. In the past I’ve...

How to configure a BIND DNS Cache in CentOS 7

Introduction I recently configured a CentOS 7 server to run BIND as a DNS caching server. This post documents the process. Although I used CentOS 7, these instructions should be equally applicable to CentOS 5 through 7, and Red Hat Enterprise Linux 5 through 7. If you...

Reset the GroundWork Monitor 6.0 Password

The GroundWork Monitor is a simple way to deploy Nagios monitoring to networks. It does a great job of monitoring Linux servers, and anything that speaks SNMP. I recently needed to make some updates to a GroundWork Community Edition VM, and found myself in a situation...

Updating a Soekris net4511’s BIOS

I performed BIOS updates on a stack of Soekris net4511s and net4521s today. Here’s a quick-and-dirty howto for anyone who wants to do the same thing from a Linux host running minicom. Note that these instructions should work on any net45xx series Soekris board,...

Install UltraVNC from within an RDP Session

Here’s how to install and start up an UltraVNC server from within an RDP session. This has been tested with UltraVNC 1.0.8 and a remote desktop session into a Windows XP Professional SP3 installation, but should work in other Windows / UltraVNC combinations as...

Update From ESXi 3.5 to ESXi 4.0 without VirtualCenter

The centerpiece of my lab is white box ESXi host. It’s been running ESXi 3.5 without issue for about a year now. A lot of my clients also run ESXi, with a few potential 3.5 to 4.0 updates coming down the pipe, so I decided it was time to update the lab to ESXi...

Directadmin and “Error Parsing Cron File”

I migrated my web hosting servers from cPanel to Directadmin earlier this year. The transition was smooth for the most part, but one problem was that users with blank crontabs with cPanel had corrupted crontabs post-migration. They could ssh in, and issue crontab -e,...

Allowing @ Signs in MediaWiki User Names

If you attempt to create a new MediaWiki account with its user name set to the same as the email address, you’ll be greeted by a cryptic “You have not specified a valid user name” error message. The reason for this is that MediaWiki forbids the @...

Changing Mosets Tree’s Root Directory Page Title

About half of the LAMP (Linux, Apache, MySQL, PHP/Python/Perl) stack websites that I develop or sysadmin for use the Joomla CMS. I like Joomla because it has a number of excellent extensions, including Mosets Tree – my favorite web directory software. A problem...

Logging into a VMware Server stuck on the “Loading…” Page

VMware Server is a handy app to run in places where server virtualization is needed, but you can’t justify the expense or effort required to setup a VMware ESXi or Xen host. One of the reoccurring problems that I run into, even on lightly loaded servers is when...