WS-431E
4G Router
www.waveshare.com
58 / 68
Figure 61 Domain name whitelist
4.7. VPN FUNCTION
VPN (Virtual Private Network) is divided into PPTP, L2TP, IPSec, OpenVPN, GRE, etc. Next,
the principles of creating VPN by these protocols are introduced respectively.
PPTP: a point-to-point tunneling protocol, which uses a TCP (port 1723) connection to
maintain the tunnel, uses the general routing encapsulation (GRE) technology to encapsulate the
data into PPP data frames and transmit them through the tunnel, and encrypts or compresses
the load data in the encapsulated PPP frames. The MPPE will encrypt the PPP frame through the
encryption key generated by the MS-CHAP V2 authentication process.
L2TP: It is a Layer 2 tunneling protocol, similar to PPTP. At present, G806 supports tunnel
password authentication, CHAP and other authentication methods, and the encryption method
supports MPPE encryption and L2TP OVER IPSec pre-shared key encryption.
IPSec: Protocol is not a single protocol, it gives a set of architecture for application and
network data security on IP layer, including network authentication protocols ESP, IKE and some
algorithms for network authentication and encryption. Among them, ESP protocol is used to
provide security services and IKE protocol is used for key exchange.
OpenVPN: Support certificate-based two-way authentication, that is, the client needs to
authenticate the server, and the server needs to authenticate the client.
GRE: GRE (General Routing Encapsulation) protocol encapsulates data packets of some
network layer protocols (such as IP and IPX) so that these encapsulated data packets can be
