It took me all night to debug the failure then try to fix it (which I couldn't, I'm not ddwrt-savvy enough - alas) and finally come up with a cheap n' dirty hack using sed, as to remove the unwanted comp-lzo directive from the GUI-generated config file. While the openVPN link comes up, the openVPN server will complain about comp-lzo being used in the remote config and report 'unknown ip protocol version=15' in its logs as soon as it gets traffic from the client.

Proper procedure would be NOT to write the directive when compression is disabled. However, there's a bug in DD-WRT which causes some grief when you don't have comp-lzo enabled: The DD-WRT GUI incorrectly writes the directive 'comp-lzo no' to the openVPN config file when LZO compression is disabled. The other thing is, you need to configure the time server for DD-WRT, at least if you want to use TLS authentication. One thing to note is, you need 'Hash Algorithm' set to 'SHA1'.

The setup of the DD-WRT is pretty easy, and if you use comp-lzo on your openVPN, then it will work right out of the box. Since I encountered some difficulties with LZO compression, I decided to write this post about it.

I successfully linked the openVPN client on a TP-LINK TL-WR1043ND Access Point running DD-WRT v24-sp2 (Release 18024 - 12/20/11) to a pfSense 2.0.1 box.

Dd wrt v24 sp2 no openvpn