I own a VPS in Rapidxen who provides me native IPV6 network.  The blog is established on the vps.

For several reasons I want to establish a VPN over IPV6 in Debian.  I searched and searched, getting more and more disappointed.  Poptop (pptpd) was written in 2007 with no ipv6 support.  Neither is xl2tpd.  After sadness and useless trying, I found a patch of xl2tpd 1.2.4 (still works with 1.2.5) written by Cheng Li, a Chinese developer.

His Article is Here:http://blog.lifetoy.org/2009/09/11/vpn-over-ipv6/

The xl2tpd can be found Here and the ipv6 patch diff can be found Here.  Patch the file and install it following the README file in doc directory.  Enjoy it!

P.S.  The patched L2TP lost some config feature such as LNC Range which, however, cannot cover the light of the patch.