Best Data DSL542 ADSL Ethernet Router User’s Guide
37
Figure 27. NAT Rule – Add Page (basic Flavor)
Follow these instructions to add an basic rule (see steps 1-4 under "The napt rul e" on page 33
for specific instructions corresponding to steps 1 and 2 below):
1. Display the NAT Rule – Add Page, select BASIC as the Rule Flavor, and enter a Rule
ID.
2. Select the interface on which this rule will be effective.
3. Select a protocol to which this rule applies, or choose ALL.
This selection specifies which type of Internet communication will be subject to this
translation rule. You can select ALL if the rule applies to all data. Or, select TCP, UDP,
ICMP, or a number from 1-255 that represents the IANA-specified protocol number.
4. In the Local Address From and Local Address To fields, type the starting and ending
IP addresses that identify the range of private address you want to be translated. Or,
type the same address in both fields.
If you specify a range, each address will be translated in sequence to a corresponding
address in a range of global addresses (which you specify in step 5).
You can create a basic rule for each specific address translation to occur. The range of
addresses should correspond to private addresses already in use on your network,
whether assigned statically to your PCs, or assigned dynamically using DHCP.
5. In the Global Address From and Global Address To fields, type the starting and
ending address that identify the pool of public IP addresses that the private addresses
should be translated to. Or, type the same address in both fields (if you also specified
a single address in step 4).
6. Follow steps 7-12 under "The napt rule" on page 33 to submit your changes.
The filter rule: Configuring a basic rule with additional criteria
Like the basic flavor, the filter flavor translates public and private IP addresses on a one-to-one
basis. The filter flavor extends the capability of the basic rule. Refer to “The basic Rule” on page
36 for a general description.
You can use the filter rule if you want an address translation to occur only when your LAN
computers initiate access to specific destinations. The destinations can be identified by thei r
IP addresses, server type (such as FTP or Web server), or both. Figure shows the fields
used to establish a filter rule.