4.
Web Management
AirLive AirMax4GW User’s Manual
103
1.
Outbound SPI:
SPI is an important parameter during hashing. Outbound
SPI will be included in the outbound packet transmitted from local gateway.
The value of outbound SPI should be set in hex formatted.
2.
Inbound SPI:
Inbound SPI will be included in the inbound packet
transmitted from remote VPN peer. It will be used to de-hash the coming
packet and check its integrity. The value of inbound SPI should be set in hex
formatted.
3.
Encryption Algorithm:
There are five algorithms can be selected: DES,
3DES, AES-128, AES-192, and AES-256. Encryption key is used by the
encryption algorithm. Its length is 16 in hex format if encryption algorithm is
DES or 48 if 3DES. However, AES-128 uses 32 length of hex format,
AES-192 uses 48 length of hex format, and AES-256 uses 64 length of hex
format. The key value should be set in hex formatted here.
4.
Authentication:
There are five algorithms can be selected: None, MD5,
SHA1, SHA2-256 and SHA2-512. Authentication key is used by the
authentication algorithm and its length is 32 in hex format if authentication
algorithm is MD5 or 40 if SHA1. However, SHA2-256 uses 64 length of hex
format. Certainly, its length will be 0 if no authentication algorithm is chosen.
The key value should be also set in hex formatted.
4.2.3.3
PPTP
The Point-to-Point Tunneling Protocol (PPTP) is a method for implementing virtual
private networks. PPTP uses a control channel over TCP and a GRE tunnel operating to
encapsulate PPP packets. The PPTP specification does not describe encryption or
authentication features and relies on the Point-to-Point Protocol being tunneled to
implement security functionality. However, the most common PPTP implementation
shipping with the Microsoft Windows product families implements various levels of
authentication and encryption natively as standard features of the Windows PPTP
stack. The intended use of this protocol is to provide security levels and remote
access levels comparable with typical VPN products.