Q: OS X Server 3.0.1 VPN inconsistent

Thank you LondonServer.  I will report this to Apple.  I understand this is important, but I tend to feel that reporting this kind of error doesn't help, because I figure Apple is already aware of this issue.  Though, I understand that every report can count.

I want to clear up my the description of my VPN issues.  VPN actually works very consistently to what particular devices will work, it's just inconsitent in which devices, as if it picks and chooses in the begining what should work from here on out.  It would appear that I made an error configuring the devices and that is why some work and some don't.  But (unless there is something I don't know) I have configured every device exactly the same.  The Account Name and Password Authentication, and the Machine Authentication are all the same.

Here's what works (and what network):

On an external network:

          My iMac, and nothing else.

On an internal (local) network:

          My iPhone 5S, and nothing else.

My iPhone will not work on an external network like it does on an internal (local) network.  My MacBook Pro will not work on any network, external or local (it is running Mountain Lion Client, my iMac is running Mavericks Client and strangly I can't get the Sever.app to enable server management, so it is still running as a Client)  I have reconfigured these devices more than once.  I have recreated a VPN configuration.  The only thing I haven't done is delete the plist in the MacBook Pro, and start over.  What is the name of the plist or other configuration file for connecting to a VPN Server in OS X Client?  Is there some other way of starting over on the iPhone other than "Delete VPN"?

Does using a Certificate for Machine Authentication make any difference with these issues?  Does using a Group name make any difference?

I would appreciate any help with this issue, including other possible options of connecting.  What I would like most, is an explaination to why some devices work and others don't.  Knowing why, would direct me to a solution.

I have contacted the Enterprise Department at Apple.  This is a known issue with L2TP.  They suggested connecting with PPTP.  This looks more promising, however instead of getting "This server has failed to respond," I get "Authentication Failed". 

I do know I have the correct settings for PPTP.  I have even "Save Configuration Profile..."  It saves a file that can be opened by iOS devices and sets up the configuration for VPN.  That still responds with "Authentication Failed".

Any suggestions on how to start over?  What files, plists, etc. should I delete? 

I appreciate any assistance in getting PPTP VPN working as a work around to the known L2PT VPN Server 3.0 issue.

I accidently clicked on "This solved my Question", I know I can't remove that, of course my own post did not solve my question.  However the previous post was of great help though!

I have replaced the racoon file located in /usr/sbin.  Restarted and then I started to be able to connect, just as well as before with Mountain Lion.  It's somewhat unreliable, as before.  At least I can always eventually connect.  Before, I was always able to connect with my iMac from home (but with nothing else), now it's inconsistent (it won't connect right now). 

Overall, this is a much better situation since I really needed to connect with iOS devices to be able to enter sales into the POS.  It's quite tedius to enter the sales later at the end of the day (when I return to the store), and I can't use the credit card swipe at all, without a connection to the main POS Server!  Thanks for your help.

I would really like to know why VPN has been somewhat inconsistent when it does work.  Is it because of random attacks on servers that are always occuring, etc.?

Thanks keg55 for the response.  The only time my iPhone ever connected was internally.  My Macbook would never connect internally or exernally.  The iPads also never connected internally or externally. 

I would get "The L2TP-VPN server did not respond." error far more often than the Authentication Failed.  Though why would Authentication fail sometimes?  Obviously the credentials were correct.  Computers generally either work or don't, I suppose with the complexity of networks (internet), there is room for fuzzy logic?

Does anyone know of any other VPN services that are far more reliable?  Or are all VPN Servers finicky?