D-Link AC1200 User Manual page 60

Section 4 - Configuration
Choose L2TP (Layer 2 Tunneling Protocol) if your Internet Service Provider
(ISP) uses a L2TP connection. Your ISP will provide you with a username and
password. Choose Basic configuration or All Settings.
Basic
Without Enable this setting to connect without a username and password.
authorization: This configuration is uncommon and is disabled by default.
Username: If Without authorization is disabled, specify the PPP username
provided by your ISP.
Password: If Without authorization is disabled, specify the PPP password
provided by your ISP.
VPN Server Specify the VPN server address provided by your ISP.
address:
Click Apply when you are done.
D-Link DIR-1210 User Manual
L2TP
56