Chapter 4: Advanced Configuration
Field
Description
ALG Type
The Application Level Gateway (ALG), if any, that was used to enable this NAT
translation (ALGs are special settings that certain applications require in order to work
while NAT is enabled).
NAT Direction
The direction (incoming or outgoing) of the translation (from the port definition).
Entry Age
The elapsed time, in seconds, of the NAT translation session.
Adding NAT Rules
This section explains how to create rules for the various NAT flavors.
In general, follow this instructions to add a rule:
1. Select
Services
>
NAT
. From the
NAT Options
drop-down list select
NAT Rule Entry
and click
[Add]
.
2. From
the
Rule Flavor
drop-down list, select the rule flavor needed. The corresponding page displays
(see sections below)
3. In
the
Rule ID
field assign a number to the rule.
The Rule ID determines the order in which rules are invoked (the lowest numbered rule is invoked
first, and so on). In some cases, two or more rules may be defined to act on the same set of IP
addresses. Once a data packet matches a rule, the data is acted upon according to that rule and is not
subjected to higher-numbered rules.
4. From
the
IF Name
drop-down list, select the interface on the ADSL Router to which this rule applies.
Typically, NAT rules apply to communication between your LAN and the Internet. Because the device
uses the WAN interface (named ppp-0 or eoa-0) to connect your LAN to your ISP, it is the usual IF
Name selection.
5. Proceed as described below for the corresponding rule.
6. When you have completed entering all information, click
[Apply]
. A page displays to confirm the
change.
7. Click
[Close]
to return to the
NAT Configuration
page. The new rule should display in the NAT Rule
table.
8. On
the
NAT Configuration
page, ensure that the
Enable
radio button is turned on.
9. On the NAT Configuration page, click
[Apply]
.
A page displays to confirm your changes.
10. Select
Admin
>
Commit & Reboot
and click
[Save]
to save your changes to permanent storage.
The napt rule: Translating between private and public IP addresses
The NAT flavor napt was used in your default configuration. The napt flavor translates all LAN-side private
source IP addresses to a single public IP address. It also translates the source port numbers to port
numbers that are defined on the NAT Global Configuration page.
1. On
the
NAT Rule - Add
page, select
NAPT
from the
Rule Flavor
drop-down list (if necessary).
Rev:01_040220
49
