What is the difference between Virtual Server and 1:1 NAT?

Zyxel_Emily
Zyxel_Emily Posts: 1,280  Zyxel Employee
First Anniversary 10 Comments Friend Collector First Answer
edited August 2022 in Networking
Question
I would like to use NAT feature to publish an internal server for external users. On the NAT Add/Edit page, there are Virtual Server and 1:1 NAT. Which one should I choose? What is the difference between Virtual Server and 1:1 NAT?

Answer
Both Virtual Server and 1:1 NAT are able to publish internal servers to Internet.
The difference between Virtual Server and 1:1 NAT is that 1:1 NAT has an additional SNAT (source NAT) while Virtual Server does not.

Configuration

In this example, create a NAT rule and select 1:1 NAT. 
Original IP: 61.222.75.17
Mapped IP: 192.168.1.33
Then the outgoing interface for the server 192.168.1.33 uses 61.222.75.17 to access Internet.


Test Result
You can check SNAT flow In MAINTENANCE > Packet Flow Explre > SNAT Status.
The source IP 192.168.1.33 access to Internet with a SNAT routing. The outgoing address will be replaced by Original IP 61.222.75.17.

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