[CentOS] Do I need a dedicated firewall?

Thu Dec 12 15:25:21 UTC 2013
Matt Garman <matthew.garman at gmail.com>

On Wed, Dec 11, 2013 at 11:00 PM, Jason T. Slack-Moehrle <
slackmoehrle at gmail.com> wrote:

> So my electricity bill is through the roof and I need to pair down some
> equipment.

If you are in the USA, get yourself a Kill-a-Watt power meter.  I'm sure
other parts of the world have similar products.  It's a device that goes
between your electrical product (e.g. server) and the wall AC outlet, and
tells you what the power draw is.  It also keeps a cumulative total for
number of Watts and Volt-Amps used in the time period it's plugged in.  (If
you have a 100% efficient PFC in your power supply, Watts will always equal
Volt-Amps.  I believe this is mandated in Europe.  But a PFC below 1.0 will
cause Volt-Amps to be higher than Watts.  In the USA you are typically
billed by Watts, but if you have a UPS, the Volt-Amp number matters.)

The question is, are you sure it's all your computers causing the spike in
your power bill?  For example, if you have an old refrigerator, those are
typically very inefficient and use more power than necessary.  The
Kill-a-Watt will tell you which devices are most power greedy.

> I have a CentOS 6.5 Server (a few TB, 32gb RAM) running some simple web
> stuff and Zimbra. I have 5 static IP's from Comcast. I am considering
> giving this server a public IP and plugging it directly into my cable
> modem. This box can handle everything with room for me to do more.
> Doing this would allow me to power down my pfSense box and additional
> servers by consolidating onto this single box.

What kind of hardware is your pfSense box?  I too have a pfSense server,
but it's on a fairly low-power Atom board.  Pulls less than 20 watts at any
given time.  The average cost of electricity in the USA is about $0.11/kwh.
 Using that number, a constant X watt draw conveniently works out to
costing $X/year.  So my pfSense box costs less than $20/year in electricity.

Obviously, if your electricity is much more expensive, it changes the

Just food for thought.