I have spent weeks on this issue.
I did a clean install of Mavericks using an external USB Boot drive and then installed OS X server (fresh and clean).
I setup a VLAN which I am not sure I needed to do.
I setup DNS internally and opened ports via NAT.
I have my registered domain pointing to my Time Capsule's Public IP
I then setup VPN in a pretty standard way...nothing else turned on.
Locally I can connect both from my iPhone 5s and Brand New Mac Book Pro with Retina (Mavericks).
Outside, its a no go for either devices and with my son's older iPhone 4s.
I turned off Back to My Mac all over the place.
I even exported the config from the Time Capsule and removed any related entries and reimported.
I have rebooted so many times and done everything I can think of.
One issue that occurs is that when I go outside my local network, DNS seems to be messed up.
A simple:
sudo killall -HUP mDNSResponder
takes care of this for me and now I'm routed through the public DNS pointing to my Time Capsule's public IP.
Not sure how best to fix this or if it's just a new Mavericks bug?
Any advice out there as I'm just considering a clean install again which ends up taking me hours to do???
Thanks in advance!