Tuesday, March 25, 2008

Switching my server to CentOS

I've been using Fedora Core (and Red Hat before it) on my home automation server. The one thing that I've never liked was the speed at which it was time to upgrade to the next release. By the time I had my server stable I was upgrading to the next release. The problem is not Fedora's as that is what the Fedora distribution is for. As one gentleman pointed out: for stable servers I could either use CentOS or Red Hat. Since you pay for Red Hat support that's a bit beyond what I need. However I would appreciate the stability of the distribution for my home automation server. So I've decided to move to CentOS 5. Before everyone argues for their favorite distribution let me say that I am familiar with the Red Hat/CentOS/Fedora layout and setup and would prefer to stay with it. Currently my server is on Fedora FC6 to get to Core 8 I'd need to backup and then restore my important files, custom daemons and other important programs after I did a fresh install. If I'm going to that much trouble why not just install CentOS and stick with extra stability? I don't need cutting edge and on a server I don't need eye candy. Since I really need to have a stable server that's the route I'm going.

Thursday, March 20, 2008


I decided it was time to sit down and start learning IPV6. And learn I did! I now have a dual stack (IPV4 and IPV6) on my network (wired and wireless). I went to Go6 and register for an IPV6 tunnel. I learned about link local addresses, site local addresses (a deprecated address), global addresses and RFC4193 addressing (kind of like RFC1918). I found this useful script for generating a valid RFC4193 network address. I've configured my radvd (Route Adverting daemon) for local use. I started finding out the details of IPV6 enabled network programming. It's not much different than what we currently do as it's mostly in the libraries. I hope to have some of my home automation software listening on both the IPV4 and IPV6 addresses.

I still have a ton of learning to do (the above only covers 3 days worth of learning). I still need to properly understand IPV4 (the current IP version used by most of the Internet) to IPV6, get a better understanding of the DNS issues, how I get a registered address for my home network or get NAT for IPV6, proper routing and anything else I don't know (which I'm sure is a lot). The reason for this sudden interest is that I'm beginning to see the need for IPV6 at work and the best way to know something is to use it on a daily basis. Having it at home will allow me to observe with the Wireshark Ethernet sniffer and give me a chance to experiment. I am also doing some experiments at work but my time at work is for work and there's very little time for play. Yes I know the benefits but deadlines are deadlines.

Oh, a couple of minor things, once you've enable IPV6 on your machines remember to restart things like your Apache daemon so they're listening on IPV6 addresses. Next to connect to the Apache server on it's IPV6 address ! use the following URL: http://[::1]/ . The ::1 is the local loopback so if it's a remote machine use it's IPV6 address (but not the link local address). This works in Firefox and above. My telnet and ssh work with IPV6 addresses (don't use the [] format, use the ::1 format instead and don't use the link local address).

Well I figure I've got years of learning to do (it took me years to get the current understanding of IPV4). Books alone won't be my sole source of learning now that I have an actual network. I've found a lot of useful information on the Internet, especially the RFC's. I'll be spending a lot of time with the RFC's. Well that's all for now.