Example 2: Many-To-One; Example 3: One-To-One And Many-To-One; Figure 27 Nat Example: Many-To-One; Figure 28 Nat Example: One-To-One And Many-To-One - ZyXEL Communications Vantage Service Gateway VSG-1200 V2 User Manual

VSG-1200 V2 User's Guide

8.2.2 Example 2: Many-to-One

The figure below shows an example where the two subscribers S1 and S2 try to establish a
secure VPN connection to VPN servers V1 and V2 respectively at the same time. In this case,
the VSG performs Many-to-One IP address translation on the WAN since the destination
address is different.

Figure 27 NAT Example: Many-to-One

The following table shows the address mapping.

Table 14 NAT Example: Many-to-One

SUBSCRIBER
S1
S2

8.2.3 Example 3: One-to-One and Many-to-One

The figure below shows an example where subscriber S1 tires to connect to VPN server V1
while subscriber S2 and S3 try to connect to the same VPN server V2 at the same time. In this
case, subscribers S1 and S2 map to the same WAN IP address since the destination is different
while subscriber S3 maps to a different WAN IP address.

Figure 28 NAT Example: One-to-One and Many-to-One

The following table shows the address mapping.
77
ORIGINAL SOURCE IP TRANSLATED SOURCE IP
10.59.1.2 211.21.21.2
10.59.1.3 211.21.21.2
Chapter 8 NAT Pool