Gateways specified in /etc/gateways should be marked passive if they are not expected to exchange routing information, while gateways marked active should be willing to exchange routing information (i.e. they should have a routed(8)? process running on the machine). Routes through passive gateways are installed in the kernel's routing tables once upon startup. Such routes are not included in any routing information transmitted. Active gateways are treated equally to network interfaces. Routing information is distributed to the gateway and if no routing information is received for a period of time, the associated route is deleted. Gateways marked external are also passive, but are not placed in the kernel routing table nor are they included in routing updates. The function of external entries is to inform routed(8)? that another routing process will install such a route, and that alternate routes to that destination should not be installed. Such entries are only required when both routers may learn of routes to the same destination.
/etc/gateways is comprised of a series of lines, each in the following format:
The net or host keyword indicates if the route is to a network or specific host.
Name1 is the name of the destination network or host. This may be a symbolic name located in /etc/networks or /etc/hosts (or, if started after named(8), known to the name server), or an Internet address specified in ``dot'' notation; see inet(3).
Name2 is the name or address of the gateway to which messages should be forwarded.
Value is a metric indicating the hop count to the destination host or network.
One of the keywords passive, active or external indicates if the gateway should be treated as passive or active (as described above), or whether the gateway is external to the scope of the routed(8)? protocol.