ZyXEL Prestige 202H Plus ISDN Router 91-003-154001B Benutzerhandbuch

P-202H Plus v2 User’s Guide

307

Chapter 33 VPN/IPSec Setup

Figure 206   Menu 27.1.1.1 IKE Setup

The following table describes the fields in this menu.

    Menu 27.1.1.1 - IKE Setup

      Phase 1
        Negotiation Mode= Main
        Pre-Shared Key= ?
        Encryption Algorithm= DES
        Authentication Algorithm= MD5
        SA Life Time (Seconds)= 28800
        Key Group= DH1

      Phase 2
        Active Protocol= ESP
        Encryption Algorithm= DES
        Authentication Algorithm= SHA1
        SA Life Time (Seconds)= 28800
        Encapsulation= Tunnel
        Perfect Forward Secrecy (PFS)= None

                    Press ENTER to Confirm or ESC to Cancel:

Press Space Bar to Toggle.

Table 102   Menu 27.1.1.1 IKE Setup

Phase 1

Negotiation 

Mode

Press [SPACE BAR] to choose from Main or Aggressive and then press [ENTER]. 

See earlier for a discussion of these modes. Multiple SAs connecting through a 

secure gateway must have the same negotiation mode. 

Pre-Shared Key

ZyXEL Device gateways authenticate an IKE VPN session by matching pre-shared 

keys. Pre-shared keys are best for small networks with fewer than ten nodes. Enter 

your pre-shared key here. Enter up to 31 characters. Any character may be used, 

including spaces, but trailing spaces are truncated. 
Both ends of the VPN tunnel must use the same pre-shared key. You will receive a 

“PYLD_MALFORMED” (payload malformed) packet if the same pre-shared key is 

not used on both ends.

Encryption 

Algorithm

When DES is used for data communications, both sender and receiver must know 

the same secret key, which can be used to encrypt and decrypt the message or to 

generate and verify a message authentication code. ZyXEL Device DES encryption 

algorithm uses a 56-bit key.
Triple DES (3DES), is a variation on DES that uses a 168-bit key. As a result, 3DES 

is more secure than DES. It also requires more processing power, resulting in 

slightly increased latency and decreased throughput.
Press [SPACE BAR] to choose from 3DES or DES and then press [ENTER].

Authentication 

Algorithm

MD5 (Message Digest 5) and SHA1 (Secure Hash Algorithm) are hash algorithms 

used to authenticate packet data. The SHA1 algorithm is generally considered 

stronger than MD5, but is slightly slower.
Press [SPACE BAR] to choose from SHA1 or MD5 and then press [ENTER].