OpenVPN between Mikrotik and OpenWRT

This is a page of details, for the intro and how to set up Windows and Linux clients, see OpenVPN.

I am writing this while testing with two three virtual machines on a Mac. Once I have the steps down, I will be transferring over to a Buffalo access point running OpenWRT 14.xx and a Mikrotik RB750 running RouterOS 5.27.

I am running my virtual machines on VirtualBox. I use images downloaded from OpenWRT and Mikrotik and install them into very minimal setups. This is handy, they boot FAST and I don't risk cutting myself off from the remote end as I do tests and experiment.

The reasons I chose to use OpenVPN over other options are

1. I can directly route packets so I don't need to mess with NAT at one end as with PPTP
2. My endpoint is hiding behind several layers of access points and routers that I don't control. OpenVPN works fine in this case.

The virtual network

Plover (Macintosh)
   192.168.56.1

    LAN (This will be the LAN in my house)

   192.168.56.101
VM1 = Router #1, OpenWRT Barrier Breaker
     76.0.0.1

     Internet

     76.0.0.2
VM2 = Router #2, Mikrotik RouterOS 6.23
    192.168.2.1

    REMOTE LAN (this will be the CDS OFFICE LAN)

   192.168.2.2
VM3 = Remote server running Debian

Creating the certificate and key files

I do this on a Ubuntu Linux box, it's the easiest way. I install the easy-rsa package which pulls in the tools needed.

This Mikrotik page has instructions on how to create the keys. Here is an abridged version.

The OpenWRT router

Refer to http://wiki.openwrt.org/doc/howto/vpn.openvpn

The Mikrotik router

Refer to same Mikrotik page as mentioned above, http://wiki.mikrotik.com/wiki/OpenVPN

The "remote" server

I happened to have a generic Debian server installed already in a VirtualBox machine, so I used it as the far end of my network to allow me to test connectivity through the two routers.