moth/doc/openwrt

This directory contains the files used to set up an OpenWRT router.


Bear in mind that the cheap consumer routers have relatively slow CPUs
and won't stand up to high volume.  This same configuration applies to
OpenWRT running on an x86 PC, or any other target of OpenWRT.  For
larger contests, it would be a good idea to use a faster machine for the
router.  I don't have any specific recommendations at this time (Oct
2010).

The router comes up as 10.0.0.1/16 on eth0.

If the router has a built-in switch, it is brought up without VLAN
support, since these switches typically only support 16 VLANs, and do
not support QinQ (double VLAN tags).  All 5 ports work like an unmanaged
switch, which ends up being handy for the contest table.

Plugging a managed switch into the router enables access to 48 VLANs,
each configured to a /16 network.  The router on VLAN number v comes up
as 10.v.0.1/16.

If the router has the ability to come up as a wireless access point, it
will do so with SSID "CTF" and IP 10.254.0.1/16.

All subnets can route to all other subnets, through the router.
10.0.0.1/16 and 10.254.0.1/16 may have a higher TTL when routed to a
VLAN (I haven't checked).  Keep in mind that anything connected directly
to the router (ie. not through the managed switch) can do its own VLAN
tagging.  This would be the way to hop on another team's subnet to do
something like check service availability in such a way as to prevent
teams from firewalling each other out.


                                    SSID "CTF"
                                  10.254.0.1/16
                                    ((Y))
                                      |
                                      -------------
                                     |   OpenWRT   |
                                      -0-1-2-3-4---
                                      /| | | | |
                                     / | | | | |
                                    /  | | | | |
                                   /  10.0.0.1/16
                                  /
              -------------------t---
             |   Managed Switch      |
              -1-2-3-4-5-...-47-48---
              /    |         |   \
             /     |         |    \
            /      |         |     \
           /       |         |      \
    10.1.0.1/16    |         |   10.48.0.1/16
                   |         |
              10.3.0.1/16    |
                             |
                        10.47.0.1/16