L2TP
L2TP is a layer 2 tunneling protocol similar to PPTP. The RLTK451 supports tunnel password authentication, MPPE, and L2TP encryption over IPSEC. To access the settings, follow the menus:
- VPN
- L2TP
In the L2TP Client section, Enable must be selected to activate it.

| Parameter | Description | Default Value |
|---|---|---|
| Server address | VPN server address or domain name | 192.168.0.2 |
| Interface | wan_4G, wan_wired or auto | auto |
| Username/Password | Obtain from VPN Server | Null |
| Encryption/Authentication | The tunnel password, MPPE (Microsoft Point-to-Point Encryption), and MSCHAP must be configured to be compatible with the VPN server. | MPPE |
| Enable Static Tunnel IP Address | When disabled, the VPN server will dynamically assign the IP address. | Disable |
| Extra Options | Add "magic number" to pppd parameters. | Null |
| NAT | The source IP address of the host behind the RLTK451 will be hidden over the remote address first. | Enable |
| Remote Subnet/Mask | When NAT is enabled, subnet communication under VPN can be provided. | 192.168.55.0/255.255.255.0 |
| Enable ping | Real-time VPN connection detection and reconnection mechanism. | Disable |
After entering the settings, click the Save & Apply button to save the settings.
After connecting to the L2TP server, you can check the connection status through the
- VPN
- VPN Status
menu.