Self-built SOHO Router

Requirements

I wanted to build a nice little access router for my home network. It should:
* do packet filtering
* do traffic shaping
* do NAT
* handle (read: separate) multiple (read: more than one) internal network segments (at least one 10baseT/100baseTX and one 802.11b WLAN segment)
* handle multiple uplinks (e.g. modem/ISDN backup for DSL/PPPoE line)
* handle IPSec encryption/decryption with at least the bitrate of my uplink (for WLAN segments)
* handle IPv6 routing/packet filtering with either native or tunneled IPv6 connectivity
* not consume too much power (-> fan- and noiseless)
* not consume too much space
* be easily updatable
* have a "nice" user interface (for a convenient definition of "nice" :-)

The WRAP Board

I've bought the WRAP.1C-2 board by PC Engines™ and use it with the LEAF Bering-uClibc which comes with a conveniently patched kernel and a lot of useful packages. I started out using Release 2.1, but have since updated to a more current version.

As you can see in the pictures, I started using the hardware in a non-professional type of assembly, and have gradually improved housing.


The WRAP Board Enclosure
Probably due to popular demand, PC Engines now also offers enclosures to fit their WRAP boards. I ordered the red anodized version from tronico.net, and the following is a short summary of the things I like and dislike about the enclosure.

Good:
* Snug fit - access to switch possible, LEDs visible.

# Same type of Philips screwdriver for both kinds of screws.
# Threaded holes available for the screws fixing the board on the enclosure base.
# The rubber pads can be glued over the screw holes without blocking access to them - the board is mounted from the inside.

* Good overall value for the money - it is a simple construction, after all.
* Nicely anodized 1mm aluminium sheet material - the red color is beautiful :) Also, the enclosure is quite sturdy, due to to the angled sheet edges.

Bad:

* You have to remove the board to change the CF medium. No idea yet whether I can machine a suitable opening/mechanism into the case. Oh, and this requires to touch six screws: The two angular SUB-D bolts and the four common "fine thread type" computer screws which hold the board.
* The screws fixing the enclosure lid to the base tap their own threads in the holes on the base when you screw them in. This creates not only the threads in the holes, but also fine aluminium swarf which will fall off and be distributed throughout the whole enclosure, probably later causing short circuits on the circuit board.


# I recommend you you follow this procedure at least twice before mounting the circuit board:

* Screw on the lid with all four screws.
* Remove the four screws, remove the lid.
* Clean the thread holes and remove all aluminium swarf you can see, be it loose or still attached (see picture, taken after three times).
* Clean the screws from swarf collected in the threads.
* Clean out the enclosure, both lid and base.

I am not sure if it is possible to tap proper threads into a 1mm aluminium sheet. If it is, it would be better if you find better screws and tap proper threads for them using the proper thread tapper. However, this is something that the PC Engines should probably address.
# Another issue about the screws fixing the lid on the base: Their head is not flush with the lid surface when you have screwed them in, but sticks out about 1mm.


* If you are very skilled and very careful, it may be possible to machine the screw holes in the lid with a countersink so that the countersunk bolts fit just level with the lid surface. But do not overdo it, or you won't be able to fix the lid with them at all.

OK, after all this musing, here is the short summary of what I would do with my next WRAP enclosure if I want to keep it really neat:

* Spray paint the anodized aluminium material with clear protective cover paint. This should avoid the ugly damaged places where the raw aluminium shows through.
* Replace the screws to hold the lid with precise countersunk bolts with fine threads. Use proper tools (tapper) to tap the threads for them, and use a countersink to have them sink deep enough in the lid to fit level with the lid surface.
* Thoroughly clean all metal filings from the case.
* Only then mount the WRAP circuit board.
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