Wan - TP-Link TL-ER604W User Manual

You can select a System Mode for your Router according to your network need.
NAT Mode

NAT (Network Address Translation) mode allows the Router to translate private IP addresses within
internal networks to public IP addresses for traffic transport over external networks, such as the
Internet. Incoming traffic is translated back for delivery within the internal network. However, the
Router will drop all the packets whose source IP addresses are in different subnet of LAN port. For
example: If the LAN port of the Router is set to 192.168.0.1 for IP address and 255.255.255.0 for the
Subnet Mask, then the subnet of LAN port is 192.168.0.0/24. The packet with 192.168.0.123 as its
source IP address can be transported by NAT, whereas the packet with 20.31.76.80 as its source IP
address will be dropped.
Non-NAT Mode

In this mode, the Router functions as the traditional Gateway and forwards the packets via routing
protocol. The Hosts in different subnets can communicate with one another via the routing rules
whereas no NAT is employed.
Note:
In Non-NAT mode, all the NAT forwarding rules will be disabled.
Classic Mode

It's the combined mode of NAT mode and Non-NAT mode. In Classic mode, the Router will first
transport the packets which are compliant with NAT forwarding rules and then match the other packets
to the static routing rules. The matched packets will be transmitted based on the static routing rules
and the unmatched ones will be dropped. In this way, the Router can implement NAT for the packets
without blocking the packets in the different subnet of the ports.

3.1.3 WAN

3.1.3.1 WAN Mode
TL-ER604W provides two adjustable WAN ports. You can set the number of WAN ports on this page.
Choose the menu Network→WAN→WAN Mode to load the following page.
Figure 3-5 System Mode
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