In IPv6 configuration, when you specify a gateway address, it is generally not necessary to include the network prefix directly in the gateway configuration.

Instead, the prefix is ​​used to define the network to which the device belongs and is set to the IP address of the device itself, not the gateway.

We explain in more detail:

IPv6 Address and Gateway Configuration

1. Device IP Address: When you configure an IPv6 address on a device, you need to specify both the address and the network prefix. For example, if your IPv6 address is 2001:db8::1 and you are on a network with a prefix /64, you would set your address as 2001:db8::1/64. This indicates that all addresses from 2001:db8::0 but also 2001:db8::ffff:ffff:ffff:ffff They are on the same subnet.
2. Gateway Address: The gateway address is simply another IPv6 address on the same subnet as your device. To configure a gateway, you only need to specify the IPv6 address of the gateway, without needing to include the network prefix. For example, if the gateway is in 2001:db8::1, you simply configure that address as your gateway.

Configuration Example

Let's say you have the following settings for your device:

• Device IPv6 address: 2001:db8:1234:5678::1/64
• Gateway IPv6 address: 2001:db8:1234:5678::ffff

Here, both addresses are within the same network block /64, but you only need to include the prefix when setting the device address. The gateway address is specified without the prefix because it is already understood to be on the same subnet defined by the device prefix.

Technical Considerations

• Subnet Consistency: It is crucial that both the device address and the gateway address are on the same subnet. Otherwise, the device will not be able to communicate with the gateway.
• Routing: Make sure any router or switch between your device and the gateway is also properly configured to handle IPv6 traffic and understand the subnetting structure used.

In summary, in IPv6, the prefix is ​​used to define the size and scope of the local network and is configured with the device address, not the gateway address. The gateway address is specified without a prefix, based on the understanding that it shares the same network prefix as the device.