I believe so.... There was no detailed explanation at the original article.
I think the suggested resolution is referring to the field "TLS Auth Key " at DD-WRT OpenVPN configuration screen.
I had tried the corresponding configration / OpenVPN connection and routing etc. successfully, but I could not prove/test if it can resolve GFW針對OpenVPN霎那間的 TLS HandShake 露餡, 而引致進行的網絡封殺..
IPIP Tunnel - just means IP within IP. I haven't used it, but the concept is simple.
Please see the following Wiki. http://en.wikipedia.org/wiki/IP_in_IP
To my understanding. IPIP tunnel doesn't involve data encryption. In Linux, you can use the command "iptunnel" to manage the tunnels.
### Establish Tunnel: [root@callisto:~#] iptunnel -?Usage: iptunnel { add | change | del | show } [ NAME ] [ mode { ipip | gre | sit } ] [ remote ADDR ] [ local ADDR ] [ [i|o]seq ] [ [i|o]key KEY ] [ [i|o]csum ] [ ttl TTL ] [ tos TOS ] [ nopmtudisc ] [ dev PHYS_DEV ]
iptunnel -V | --version
Where: NAME := STRING
ADDR := { IP_ADDRESS | any }
TOS := { NUMBER | inherit }
TTL := { 1..255 | inherit }
KEY := { DOTTED_QUAD | NUMBER }
IP-IP Tunnel
=========
Tunneling is a somewhat misleading term; there is nothing to actually "dig" through. Network tunnels consist only of two endpoints (an encapsulator and a decapsulator), gateways, a passenger, and a transport protocol. Granted, these are point-to-point links. In between, ordinary destination prefix-based routing and best-effort delivery over IP infrastructures occurs.
In the case of IP-IP tunneling (RFC 1853, RFC 2003), an IP datagram (passenger) travels encapsulated in another IP datagram (transport). The inner IP header is not changed by the encapsulator, except to decrement the Time To Live (TTL) by 1 if the tunneling is carried out as part of forwarding the datagram. The decapsulator does not alter the TTL value, though. An encapsulator must not encapsulate an inner datagram with TTL=0; and vice versa, if after decapsulation the inner TTL equals 0, the decapsulator must discard the datagram.
There is no tunnel management besides the usual Internet Control Message Protocol (ICMP) mechanisms. Obvious applications are policy routing, multicasting and tunneling of RFC 1918 address space, connecting discontinuous subnetworks, providing multiprotocol transport, and overcoming hop-count limits of certain protocols. However, IP-IP tunnels don't work from behind Network Address Translation (NAT) gateways. RFC 2003 does not specify an authentication mechanism; however, header authentication could be used in between the original inner and transport outer header.
IP-IP tunneling is supported by Linux and all BSD operating systems. They are not necessarily compatible with the Cisco IP-IP tunnel implementation. Cisco has introduced an authentication option. Take a look at the article "Configuring Logical Interfaces".
You can refer to the following eTutorial for the details.