ZyXEL Communications ZyWALL 10/10, User Manual

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ZyWALL 10/10 II/50 Internet Security Gateway
NAT 9-23
9.5.4 Example 4: NAT Unfriendly Application Programs
Some applications do not support NAT Mapping using TCP or UDP port address translation. In this case it
is better to use
Many-One-to-One mapping as port numbers do not change for Many-One-to-One (and
One-to-One )
NAT mapping types. The following figure illustrates this.
Figure 9-21 NAT Example 4
Other applications such as some gaming programs are NAT unfriendly because they
embed addressing information in the data stream. These applications won’t work
through NAT even when using One-to-One and Many-One-to-One mapping types.
Follow the steps outlined in example 3 above to configure these two menus as follows.