ZyXEL Communications Vantage CNM 2.3 User Manual page 655

Case D: Two or more subscribers have the same IP address.
By converting all private IP addresses to the WAN IP address, the device allows
subscribers with different network configurations to access the Internet. However,
there are situations where two or more subscribers are using the same private IP
address. This may happen when a subscriber is configured to use a static (or
fixed) IP address that is the same as the IP address the device DHCP server
assigns to another subscriber acting as a DHCP client.
In this case, the subscribers are not able to access the Internet.
Figure 368 IP Address Conflicts: Case D
This problem can be solved by adding a VLAN-enabled switch or set the computers
to obtain IP addresses dynamically.
Vantage CNM User's Guide
Appendix E IP Address Assignment Conflicts
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