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Routing
General Information
The router connects several subnets and assumes forwarding of data packets from the devices in the respective subnets into other subnets. This means that incoming data packets are routed to certain network devices according to certain rules defined by the user.
The routes determine whereto packets are forwarded. They are stored in the routing table of the router. The routes will only be entered into the routing table if the interface selected when creating the route is started.
Adding a route
Routes are added in the Routing menu on the Static routes page. When adding the route, it will be differentiated between a default route and a network route. Routes for OpenVPN networks are added in the Routing menu on the OpenVPN routes page.
Network route
In case of a network route, the route is only effective for data packets that are directed to the network specified here (e.g. 192.168.101.0/24) or the network address specified here (e.g. 192.168.101.11).
Default route
A default route forwards the data packets to the configured gateway, for which no dedicated route has been found in the routing table.
Gateway
The gateway can be defined by a dynamically received IP address, by a static IP address or by specifying an interface.
Dynamically received IP address
For the dynamically received IP address, the DHCP client of the interface must be activated that an address can be assigned. The DHCP client can be activated in the Interfaces menu on the IP net page of the respective network.
Static IP address
A static IP address can also be assigned to the gateway.
Interface
An interface (a VPN tunnel for example) can also act as a gateway.
Priority of the route
A priority must be specified if several data routes are created in case the associated interfaces are started simultaneously. The route with the lowest priority number will always be effective then. If there is no priority specified, the route which has been entered first will be effective.
Routing table
The routes entered in the routing table can be displayed in the Status menu on the System details / Routes page. It must be observed here that the routes will only be entered with the start of their interface.
Processing the routing table
The router will investigate each incoming data packet and proceed as follows:
| Is the packet addressed to the router? | Yes → | Processing If the destination address of the packet corresponds to the IP address of the router, it has arrived at the destination and can be processed. |
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| No ↓ |
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| Is the packet addressed to a subnet of the router? | Yes → | Forwarding to the subnet The destination address will be masked with the subnet mask to determine whether the packet is addressed to the own subnet and can be forwarded. |
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| No ↓ |
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| Is the route to the recipient of the packet known? | Yes → | Forwarding via the known route The routing table will be processed one after the other. If a route is found that corresponds to the packet, it will be forwarded to the gateway address defined in the route. |
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| No ↓ |
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| Is a default gateway defined? | Yes → | Forwarding via the default gateway If no route is found that corresponds to the packet, it will be forwarded to the default gateway address. |
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| No ↓ |
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| The data packet will be dropped. |