ZyXEL Communications Prestige 661H Series, User Manual

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Prestige 661H/HW Series User’s Guide
181 Chapter 15 VPN Screens
The following figure depicts an example where three VPN tunnels are created from Prestige
A; one to branch office 2, one to branch office 3 and another to headquarters. In order to
access computers that use private domain names on the headquarters (HQ) network, the
Prestige at branch office 1 uses the Intranet DNS server in headquarters. The DNS server
feature for VPN does not work with Windows 2000 or Windows XP.
Figure 82 VPN Host using Intranet DNS Server Example
If you do not specify an Intranet DNS server on the remote network, then the VPN host must
use IP addresses to access the computers on the remote network.
15.8 ID Type and Content
With aggressive negotiation mode (see Section 15.11.1 on page 189 ), the Prestige identifies
incoming SAs by ID type and content since this identifying information is not encrypted. This
enables the Prestige to distinguish between multiple rules for SAs that connect from remote
IPSec routers that have dynamic WAN IP addresses. Telecommuters can use separate
passwords to simultaneously connect to the Prestige from IPSec routers with dynamic IP
addresses (see
Section 15.17 on page 199 for a telecommuter configuration example).
Regardless of the ID type and content configuration, the Prestige does not allow you to save
multiple active rules with overlapping local and remote IP addresses.
With main mode (see Section 15.11.1 on page 189 ), the ID type and content are encrypted to
provide identity protection. In this case the Prestige can only distinguish between up to 12
different incoming SAs that connect from remote IPSec routers that have dynamic WAN IP
addresses. The Prestige can distinguish up to 12 incoming SAs because you can select between
three encryption algorithms (DES, 3DES and AES), two authentication algorithms (MD5 and
SHA1) and two key groups (DH1 and DH2) when you configure a VPN rule (see
Section 15.12
on page 190 ). The ID type and content act as an extra level of identification for incoming SAs.
The type of ID can be a domain name, an IP address or an e-mail address. The content is the IP
address, domain name, or e-mail address.