Just a note for those folks with well-worn bookmarks to this post on Ed Marczak’s blog, Radiotope.com, for authenticating VPN connections with Mac OS X Server’s Open Directory, which is still valid today. When trying to use the System Preferences VPN client/network adapter with the built-in L2TP server in Sonicwall, though, I was curious why OD auth wasn’t working for me, but users that were local to the Sonicwall were. Having been a while since the last time I’d set it up, I went on a search engine spelunking and found a link that did the trick.
In particular, a comment by Ted Dively brought to my attention the fact you need to change the order(in the VPN sidebar item, L2TP Server, when the Configure button pop-up is clicked, it’s under the PPP tab) that the L2TP service is configured to use for authentication type, PAP instead of the more standard MSCHAPv2.
We hope that is of help to current and future generations.