ZyXEL Communications 2 Plus User Manual
Chapter 17 Network Address Translation (NAT)
ZyWALL 2 Plus User’s Guide
337
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
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 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.
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.
Port Forwarding
Rules
The bar displays how many of the ZyWALL's possible port forwarding rules are
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
Rules
The bar displays how many of the ZyWALL's possible trigger port rules are
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.
Table 95 ADVANCED > NAT > NAT Overview (continued)
LABEL
DESCRIPTION