Figure 28-19 Nat Example 4 - ZyXEL Communications Internet Security Gateway ZyWALL 2 Series User Manual

ZyWALL 2 Series User's Guide
28.4.4 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 28-19 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.
NAT 28-15