ZyXEL Communications NBG410W3G Series User Manual

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Chapter 12 Network Address Translation (NAT)
NBG410W3G Series User’s Guide
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12.4  NAT Address Mapping   
Click ADVANCED > NAT > Address Mapping to open the following screen. 
12.4.1  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 
 for more on NAT.
Use this screen to change your ZyXEL Device’s address mapping settings.  
Ordering your rules is important because the ZyXEL Device applies the rules in the order that 
you specify. When a rule matches the current packet, the ZyXEL Device 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. 
Port Forwarding 
Rules
The bar displays how many of the ZyXEL Device's possible port forwarding rules are 
configured. The first number shows how many port forwarding rules are configured 
on the ZyXEL Device. The second number shows the maximum number of port 
forwarding rules that can be configured on the ZyXEL Device.
Port Triggering 
Rules
The bar displays how many of the ZyXEL Device's possible trigger port rules are 
configured. The first number shows how many trigger port rules are configured on 
the ZyXEL Device. The second number shows the maximum number of trigger port 
rules that can be configured on the ZyXEL Device.
Copy to WAN 2 
(and Copy to 
WAN 1)
Click Copy to WAN 2 (or Copy to WAN 1) to duplicate this WAN interface's NAT 
port forwarding or trigger port rules on the other WAN interface.
Note: Using the copy button overwrites the other WAN interface's 
existing rules.
The copy button is best suited for initial NAT configuration where you have 
configured NAT port forwarding or trigger port rules for one interface and want to use 
similar rules for the other WAN interface. You can use the other NAT screens to edit 
the NAT rules after you copy them from one WAN interface to the other.
Apply
Click Apply to save your changes.
Reset
Click Reset to begin configuring this screen afresh.
Table 67   ADVANCED > NAT > NAT Overview (continued)
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