Build your own gateway firewall

Step 3 Putting it all together

Below are some pictures we took when my brother and I were building our NAS. I'll add comments to each step when I find the time, but, for now, here's the overview (in order):

» Clean everything off. Use compressed air to remove the dust from electrical components. A paintbrush can be used to remove dust from the fans. Do NOT use the paintbrush on electrical components! This may create static and damage your parts.
» Mount the motherboard in the case. It's best to do this now, because you might not be able to later.
» Mount the PSU. Again, do this now, because you may not be able to once you install the CPU, HSF, and drives. Do NOT plug the PSU into the motherboard, and make sure that the PSU is powered off and unplugged.
» Place the CPU in the retention mechanism. Be sure to properly ground yourself first by plugging in your PSU and touching the case as you unplug your PSU. Anti-static wristbands work even better. Do not force the CPU into the socket. Make sure you insert the CPU in the correct orientation. Use the pins and socket as reference. It should either slide in with a little pressure (Slot CPUs) or drop right in (Socket CPUs). After it is in place, be sure to fasten any latches or switches that hold the CPU in place.
» Grease the CPU. Thermal compound is used to fill the microscopic air pockets between your CPU and HSF with a thermally-conductive material. If your CPU has a heatspreader (extra metal around the core to provide strength), apply a dime-sized amount of thermal compound to the center of the heatspreader. If the CPU does NOT have a heatspreader, apply a small dab of thermal compound. Spread the compound around using a piece of stiff paper (a business card works great). If you get a little compound somewhere other than the top of the CPU, a little isopropyl alchol (rubbing alcohol, not booze) and some Q-tips will help to remove it. When you're finished, you should have a very thin layer of thermal compound covering the entire surface of the CPU.
» Install the HSF. This is often the most nerve-racking part. Sometimes it takes some force to secure the HSF retention mechanism. First, examine the retention mechanism to learn how it works. This will give you an idea of how to properly secure it, and ways that you may damage it. Next, take your time and carefully apply the appropriate force to secure the HSF. If you see your motherboard flex, or you're using enough force to move your case, you're probably doing something wrong. After you have the heatsink on, install the fan. Also, BE SURE YOU PLUG THE CPU FAN IN.
» Install the ram. Look at the DIMM slots on your motherboard and make sure that you are inserting the RAM correctly. There should be a ridge in the slot itself, and a notch in your RAM to help you determine the correct orientation of the RAM. You will also need to open the clips on the ends of the DIMM slots to allow insertion of the RAM. Now, carefully apply an even downward force to the RAM until you hear a click. This is the sound of the side fasteners locking the RAM modules into place.
» Install the drives. Because of their size, the drives should be installed next. Place the drives in their appropriate locations, and connect the power and data cables. Your harddrive should be connected to your primary IDE channel (labelled something like IDE_0 or Primary or 1). Your optical drive can share the same ribbon as your hard drive; however, if you plan on removing it, it's better to connect it to the secondary IDE channel for easy removal. You may notice an extra plug on the back of your optical drive. This is for digital audio. It's safe to ignore this.
» Install the I/O devices. Use a steady downward force to secure the PCI, AGP, and/or ISA cards in their appropriate slots. Be careful not to flex the cards while you're installing them. Sometimes the VGA slot has a little pin to better secure the video card. Should you ever remove the video card, you will need to release this pin first.
» Install any case fans. Consider the environment where the firewall will be placed, and provide enough fans to maintain adequate cooling. Larger fans are more quiet and move less air. If you're placing your firewall in an air-conditioned environment, and you have a decent sized case, one fan or no fans should provide enough cooling.
» Connect the power, reset, HD activity LED, Motherboard status LED, and system speaker. On most motherboards, the connections for all of these can be found in two rows of pins somewhere on the motherboard. Please refer to any documentation you can find to attach your power switch and indicators to the correct location. One trick to help locate the power-on or reset pins if you are POSITIVE that you have found the correct set of headers is to use a screwdriver to temporarily short jumpers until the computer turns on. You will have to do this after you connect the PSU to the motherboard (obviously).
» Connect the PSU to the motherboard. Connect the 20- or 24-pin connector to the motherboard. You may find an extra 4-pin connector on the motherboard also. This is to provide additional power to the motherboard. Often times it is unnecessary to connect this, because we will not be drawing enough power to connect it. Try powering on the motherboard without it, and if that fails, plug it in and try again.
» Power on and pray. This is the moment of truth. Did you install your RAM correctly? Is your CPU fan plugged in? If you hear more than a single short beep from your system speaker (you plugged that in right?), then something is probably wrong. Power off immediately and check your documentation to confirm that you've done everything. The beeps that you heard (error codes) can be used to help diagnose the problem.