Chapter 17 Network Address Translation (NAT)

 

Table 95 ADVANCED > NAT > NAT Overview (continued)

 

LABEL

DESCRIPTION

 

Port Forwarding

The bar displays how many of the ZyWALL's possible port forwarding rules are

 

Rules

configured. The first number shows how many port forwarding rules are configured

 

 

on the ZyWALL. The second number shows the maximum number of port

 

 

forwarding rules that can be configured on the ZyWALL.

 

 

 

 

Port Triggering

The bar displays how many of the ZyWALL's possible trigger port rules are

 

Rules

configured. The first number shows how many trigger port rules are configured on

 

 

the ZyWALL. The second number shows the maximum number of trigger port rules

 

 

that can be configured on the ZyWALL.

 

 

 

 

Apply

Click Apply to save your changes back to the ZyWALL.

 

 

 

 

Reset

Click Reset to begin configuring this screen afresh.

 

 

 

17.4 NAT Address Mapping

Click ADVANCED > NAT > Address Mapping to open the following screen.

17.4.1 What NAT Does

In the simplest form, NAT changes the source IP address in a packet received from a subscriber (the inside local address) to another (the inside global address) before forwarding the packet to the WAN side. When the response comes back, NAT translates the destination address (the inside global address) back to the inside local address before forwarding it to the original inside host. Note that the IP address (either local or global) of an outside host is never changed.

See Section 17.1 on page 331 for more on NAT.

Use this screen to change your ZyWALL’s address mapping settings.

Ordering your rules is important because the ZyWALL applies the rules in the order that you specify. When a rule matches the current packet, the ZyWALL takes the corresponding action and the remaining rules are ignored. If there are any empty rules before your new configured rule, your configured rule will be pushed up by that number of empty rules. For example, if you have already configured rules 1 to 6 in your current set and now you configure rule number 9. In the set summary screen, the new rule will be rule 7, not 9. Now if you delete rule 4, rules 5 to 7 will be pushed up by 1 rule, so old rules 5, 6 and 7 become new rules 4, 5 and 6.

 

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ZyWALL 2 Plus User’s Guide