For example, if you have an FTP server (port21) at
192.168.8.5, a mail server (port110) at 192.168.8.6,and a
VPN server at 192.168.8.7,then you need to specify the virtu-
al server as:
21
192.168.8.5
110
192.168.8.6
1723
192.168.8.7
Please refer to Appendix A for some well-knwn service port.
4.5 DMZ
DMZ (DeMilitarized Zone) is a zone, which is not protected by
firewall. It means all computers in DMZ are dangerous and
subject to be attacked/accessed by Internet intruder/hacker.
However the advantage is that all computers in DMZ are
totally exposed to Internet, thus all of them gain the full
access right privilege to outside Internet. In such case,
Theoretically all Internet applications should be compatible
with them (because there is not any interference from firewall
function).
There are more and more Internet applications that need 2-
way access right (like video and/or audio conference, on-line
game..). Broadband Router provide the similar features to
make some computers in LAN to have unrestricted 2-way
access privilege. As a result, all computers in DMZ are most
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