ATL Telecom AM30 - Manual (Page 74)

74 ATL Telecom User Guide
AM30
The Basic rule: Performing 1:1 translations
The Basic flavor translates the private (LAN-side) IP address to a public (WAN-side) address,
like NAPT rules. However, unlike NAPT rules, Basic rules do not also translate the port
numbers in the packet header; they are passed through untranslated. Therefore, the Basic
rule does not provide the same level of security as the NAPT rule.
Figure 36 shows the fields used for adding a Basic rule.
Figure 36. NAT Rule – Add Page (Basic Flavor)
Follow these instructions to add an BASIC rule (see steps 1-4 under "The NAPT rule" on
page 68 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 ANY.
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 Internet Assigned Numbers Authority
(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