ZyXEL Communications P-661H-61, Руководство пользователя, Страница: 235 / 404

Chapter 16 VPN
P-661HNU-Fx User’s Guide
235
DNS server in headquarters. The DNS server feature for VPN does not work with
Windows 2000 or Windows XP.
Figure 105 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.
16.6.8 ID Type and Content
With aggressive negotiation mode (see Section 16.6.6 on page 234 ), 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 16.6.11 on page 237 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 16.6.6 on page 234 ), 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
Remote
IPSec Router
HQ
10.1.1.1/200
Intranet DNS
10.1.1.10
ISP DNS Servers
212.54.64.170 212.54.54.171
LAN
DNS:212.54.64.170
212.54.64.171
A
VPN DNS: 10.1.1.10
= VPN Tunnel
2
192.168.1.1/50
3
172.16.1.1/50
1