Nortel BCM 3.7, Manual

Page: 742 / 1004

742 Configuring an Interface with NAT
N0008589 3.3
Configuring NAT to change the source IP address used for WAN
traffic
Normally, when traffic originates from the Business Communications Manager, the source IP
address of the data packets is the IP address of interface that is on the edge. For example, if the
traffic is sent out of the WAN1 interface, the source IP address of the data packets is the IP address
of WAN1.
You can use NAT rules to change the source IP address of the data packets to one of the other data
network interfaces. To create this type of NAT rule, you must comply with the following rules:
• The IP addresses you enter must be addresses that can be correctly routed.
• The IP address you enter in the Public IP box must be the IP address of one of the other data
interfaces (for example, LAN1 or LAN2).
• The source or destination port must match the ports specified in the Public Port Range box.
• These NAT rules are only available on the WAN interface and the ISDN WAN backup
interface. They are not available on the V.90 WAN backup interface.
For an example of this configuration, refer to “Example 3: Changing the source IP address of
WAN traffic” on page 745 .
Deleting a Rule to an Interface
1 Click the Rule Setting tab.
The Rule Setting screen appears.
2 Click the rule you want to delete.
3 On the Configuration menu, click Delete Rule .
A message appears that asks you to confirm the deletion.
4 Click the Yes button.
Configuring the Rule order
1 When you finish adding rules, click the Rule Order tab.
The Rule Order screen appears.
2 In the Rule Order box, configure the order of the rules.
3
Press Tab to update the screen.
Note: Configure the rule order from most specific to most general. For example, a TCP
rule for one port should come before a general rule for all TCP traffic. IP rules should
come last.