ZyXEL Communications P-2602HWLNI, Руководство пользователя, Страница: 281 / 496

Chapter 18 VPN Screens
P-2602HWLNI User’s Guide
281
The following figure depicts an example where three VPN tunnels are created from ZyXEL
Device 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
ZyXEL Device 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 160 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.
18.9 ID Type and Content
With aggressive negotiation mode (see Section 18.12.1 on page 289 ), the ZyXEL Device
identifies incoming SAs by ID type and content since this identifying information is not
encrypted. This enables the ZyXEL Device 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 ZyXEL Device from IPSec routers
with dynamic IP addresses (see
Section 18.18 on page 297 for a telecommuter configuration
example).
Regardless of the ID type and content configuration, the ZyXEL Device does not allow you to
save multiple active rules with overlapping local and remote IP addresses.
With main mode (see
Section 18.12.1 on page 289 ), the ID type and content are encrypted to
provide identity protection. In this case the ZyXEL Device can only distinguish between up to
12 different incoming SAs that connect from remote IPSec routers that have dynamic WAN IP
addresses. The ZyXEL Device 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 18.13 on page 289 ). 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.