VPN Screens
When you use one of these encryption algorithms for data communications, both the sending device and the receiving device must use the same secret key, which can be used to encrypt and decrypt the message or to generate and verify a message authentication code. The 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 increased latency and decreased throughput. This implementation of AES uses a 128-bit key. AES is faster than 3DES.

ZyWALL 2 Series User’s Guide

 

Table 14-8 Advanced IKE VPN Rule Setup

 

 

LABEL

DESCRIPTION

 

 

Enable Replay

As a VPN setup is processing intensive, the system is vulnerable to Denial of Service

Detection

(DoS) attacks The IPSec receiver can detect and reject old or duplicate packets to protect

 

against replay attacks. Select YES from the drop-down menu to enable replay detection,

 

or select NO to disable it.

Local Port

Start "0" is the default and signifies any port. Type a port number from 0 to 65535. Some of the most common IP ports are: 21, FTP; 53, DNS; 23, Telnet; 80, HTTP; 25, SMTP; 110, POP3.

End Type a port number in this field to define a port range. This port number must be greater than that specified in the previous field. If Local Port Start is left at 0, Local Port End will also remain at 0.

Remote Port

Start Type up to 32 characters to identify this VPN policy. You may use any character, including spaces, but the ZyWALL drops trailing spaces.

End Enter a port number in this field to define a port range. This port number must be greater than that specified in the previous field. If Remote Port Start is left at 0, Remote Port End will also remain at 0.

Phase 1

Negotiation Mode Select Main or Aggressive from the drop-down list box. Multiple SAs connecting through a secure gateway must have the same negotiation mode.

Encryption Select DES, 3DES or AES from the drop-down list box.

Algorithm

14-26