Fiddler – monitor HTTP requests from your browser

Fiddler is invaluable for monitoring HTTP requests from your browser. If you’re investigating HTTP header usage and the effort on caching static content, Fiddler is definitely the way to go, since using the Developer Tools in IE, Chrome or FireBug in Firefox don’t always give you an accurate picture of the actual outgoing HTTP requests. IE is the worst… its developer tool shows HTTP requests going out even though the files are being retrieved from cache. If you really want to see what’s going on then you need something like Fiddler.

To review requests against a server running locally (against localhost), there’s a number of tips in the docs here, but the simplest approach seems to be to use your own IP address (actual address, not instead of localhost or any of the other approaches listed on this page. It works without any other changes.

Installing VirtualBox Guest Additions for a CentOS Guest

The steps to prepare a CentOS guest for installing the VirtualBox Guest Additions are outlined here, but since it references a few other pre-req steps, here’s a list of all the steps I took to get all the dependencies installed before you can install the Guest Additions:

Install yum-priorities (

yum install yum-priorities

Install RPMForge (



rpm --import

rpm -i rpmforge-release-0.5.2-2.el6.rf.*.rpm

Install dkms:

yum --enablerepo rpmforge install dkms

Install dev tools and kernel development:

yum groupinstall "Development Tools"
yum install kernel-devel





Fedora 18 & 19 – terrible performance on Virtual Box

I’m not sure what the deal is with Fedora 18 & 19 but the performance running under Virtual Box in Windows, regardless of how much memory you throw at the VM, really is unbearably slow. I had 18 installed for a while but haven’t used it for several months. I just fired it up again and it’s unusable. Downloaded 19 and started the install and it took a couple of hours. I might have something else going on on my laptop that slowing down the performance, but as it is it’s unusable.

I was looking for a RHEL derivative other than Oracle Linux since I wasn’t prepared wait to download the massive disk images which are several GB (really?!). I just realized though that CentOS is RHEL compatible. Very cool. Will download and see if it’s more usable under Virtual Box.