User`s guide

Configuring Client Services
2-8
Network Address Translation – NAT
Network Address Translation can be used to give multiple users access to the Internet with
a single user account, or to map the local address for an IP server (such as Web or FTP) to
a public address. This secures your network from direct attack by hackers, and provides
more flexible management by allowing you to change internal IP addresses without
affecting outside access to your network.
Virtual Server
If you configure the RoamAbout R1 as a virtual server, remote users accessing services
such as the Web or FTP at your local site via public IP addresses can be automatically
redirected to local servers configured with private IP addresses. Depending on the
requested service (TCP/UDP port number), the RoamAbout R1 redirects the external
service request to the appropriate server (located at another internal IP address).
The WAN interface must have a fixed IP address to utilize this function. For example, if
you set Type/Public Port to TCP/80 (HTTP or Web) and the Private IP/Port to 192.168.2.2/
80, then all HTTP request from outside users will be transferred to 192.168.2.2. Therefore,
by just entering the IP Address provided by the ISP, Internet users can access the service
they need at the local address to which you redirect them.
Some of the more common TCP service ports include:
• HTTP: 80
• FTP: 21
• Telnet: 23
• POP3: 110.
NAT must be enabled to provide multi-user access to the Internet, or to use
the Virtual Server function.
NOTE