Example 4: Nat Unfriendly Application Programs - ZyXEL Communications ZyWALL 10/10 User Manual

ZyWALL 10/10 II/50 Internet Security Gateway

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.
NAT 9-23