Multiple Network Address Translation and IP Setup
Public Addresses | Private Addresses |
206.1.1.1 | 192.168.1.1 |
206.1.1.2 | 192.168.1.2 |
206.1.1.3 | 192.168.1.3 |
206.1.1.4 | 192.168.1.4 |
206.1.1.5 | 192.168.1.5 |
206.1.1.6 | 192.168.1.6 - 254 |
IP Host | NAT Type |
Router | 1:1 Static |
Web Server | 1:1 Static |
Mail Server | 1:1 Static |
FTP Server #1 | 1:1 Static |
FTP Server #2 | 1:1 Static |
LAN Users | 1:Many PAT |
In order to support this type of mapping, the private addresses and public addresses are separated and are assigned to ranges. Each range consists of a contiguous set of one or more addresses. The router allocates the addresses in that range based on the type (static or PAT), and other relevant attributes. The range defines the rules for distributing the exterior addresses. NAT maps, kept in a list similar to a firewall or filter list, contain the private addresses and the name pointer of the range to use to get a public address. The maps function as an access control list to the resource contained in the range.
Features
The Netopia R2020 Router features the following:
■Default behavior consistent with previous firmware versions, including PAT to a DHCP- or
■
An internal private address is permanently mapped to an external address. TCP and UDP port addresses are not altered.
■Multiple
PAT addresses may be assigned to specific private address subnets; not all internal machines need to be included on a PAT remapping list.
■Coexistent mapped and unmapped traffic on a public interface.
If the router's IP address is not included in a NAT list, it will be invisible to the external network.
■Mapped services (exports) may use multiple public addresses.
■NAT maps per interface, similar to the filter rules.
Supported traffic
MultiNat supports the following IP protocols:
■PAT: TCP/UDP traffic which does not carry source or destination IP addresses or ports in the data stream (i.e., HTTP, telnet, ‘r’ commands, tftp, NFS, NTP, SMTP, NNTP, etc.).
■Static NAT: All IP protocol traffic which does not carry or otherwise rely on the source or destination IP addresses in the data stream.
