November 25, 2013

Connecting to OS X VPN on Windows 7 and Later

When setting up windows machine’s for VPN access to OS X server’s builtin VPN service there is some tweaking that I have always found necessary.

  1. Add this to your registry:

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\PolicyAgent] "AssumeUDPEncapsulationContextOnSendRule"=dword:00000002

  1. Open secpol.msc (click start > search for secpol.msc)
  • Local Policies > Security Options
  • Network Security : LAN Manager Auth Level…
  • Set to: Send LM & NTLMv2 - UseNTLMv2…


  • Network Security : Minimum session security… clients
  • uncheck “Require 128-bit encryption”
  1. Restart PC

  2. Create VPN Connection on Windows 7

  • Host Name: (server IP or
  • PPP Settings : Enable LCP (only)
  • Type: L2TP/IPSec
  • Pre-shared key : yoursharedsecret
  • Data encryption : Optional encryption
  • Allow CHAO and CHAPv2
  1. Router on server-side must allow VPN Passthrough and forward ports: 50, 51, 500, 548, 1701, 1723, 4500 to the server box. Also, do not filter anonymous internet requests, multicast or NAT Redirection but enable SPI Firewall.

Following these steps should produce a working VPN connection on Windows 7 when connecting to a VPN provided by OS X server.

© Lars Cromley 2017