I've found this little tutorial (simplified) on how to use PPTP on OS X or Iphone to connect to PPTP services provided by pfSense® software.

 

On pfSense box

  1. VPN --> PPTP -> Configuration (tab)
  2. Select "Enable PPTP Server"
  3. Server Address - "Enter the WAN IP"
  4. Remote Address Range - "Pick a range of 16 addresses that are available on your network that is also evenly divisible by 16" i.e. 192.168.1.112 or 192.168.1.128
  5. I would recommend selecting the checkbox that requires 128-bit encryption. 
  6. VPN --> PPTP -> Users (tab)
  7. Click "+" to add user
  8. Fill in username and password. You can leave IP blank to just take the first address in the pool of 16.
  9. Firewall --> Rules --> PPTP VPN (tab)
  10. Added a rule to allow all traffic to talk to everything (if you need more specifics, let me know)

 

iPhone/iPod Touch

  1. Settings --> General --> Network --> VPN
  2. Add VPN Configuration
  3. Select PPTP
  4. Fill in generic Description
  5. Enter the IP address of your WAN interface
  6. The username that was created above
  7. RSA SecurID : OFF
  8. Enter password created above
  9. Encryption Level: Auto
  10. Send All Traffic: ON
  11. Save
  12. Turn ON VPN

 

I was able to disable wireless, then VPN back into my home network over the 3G network and access services that are behind the pfSense® firewall. I was able to web into the pfSense® software configuration page.

 

Original thread available here.