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Open Suse Router
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routed(8) System Manager's Manual routed(8) NAME
routed - Manages network routing tables SYNOPSIS
/usr/sbin/routed [-q | -s] [-dgt] [logfile] The routed daemon manages the network routing tables. FLAGS
Enables additional debugging information, such as bad packets received, to be logged. The routed daemon remains under control of the host that started it; therefore, an interrupt from the controlling host stops the routed process. Causes the routing daemon to run on a gateway host. This flag is used on internetwork routers to offer a route to the default destination. Inhibits the routed daemon from supplying Routing Information Protocol (RIP) data. The -q flag conflicts with the -s flag. Do not use the -q and -s flags together. Causes routed to supply RIP information even if it is not functioning as an Internet router. The -s flag conflicts with the -q flag. Do not use the -s and -q flags together. Causes all packets sent or received to be written to standard output. The routed daemon remains under control of the host that started it; therefore, an interrupt from the controlling host stops the routed process. DESCRIPTION
Use the routed daemon to manage the RIP only. Use gated to manage RIP plus other protocols. When routed starts, it finds any interfaces to directly connected hosts and networks that are configured into the system and marked as up. If multiple interfaces are present, routed assumes that the local host forwards packets between networks. The routed daemon transmits an RIP request packet on each interface (using a broadcast packet if the interface supports it) and then enters a loop, listening for RIP routing requests and response packets from other hosts. In addition, if routed is to supply RIP information to other hosts, it periodi- cally sends RIP update packets (containing copies of its routing tables) to any directly connected hosts and networks. When routed receives a RIP request packet and can supply RIP routing information, (the -s flag is set), it generates a reply (response packet) based on the information maintained in the kernel routing tables. The response packet contains a list of known routes, each marked with a hop count metric (the number of host-to-host connections in the route). The metric for each route is relative to the sending host. A metric of 16 or greater is considered to be infinite, or beyond reach. Updating Routing Tables If RIP processing is enabled, routed uses information contained in the RIP response and update packets from other hosts to update its rout- ing tables. However, routed uses the information in the RIP routing packet to update the tables only if at least one of the following con- ditions exists: No routing table entry exists for the destination network or host, and the metric associated with the route is finite (that is, the metric is less than 16). The source host of the packet is the router in the existing routing table entry. The routing table entry is old and the new information is about a route that is at least as efficient as the existing route. The new route is shorter than the one that is currently stored in the routing tables. (Note that routed determines relative route length by comparing the new metric with the one stored in the routing table.) When routed updates its internal routing tables, it generates an RIP update packet to all directly connected hosts and networks. Before updating the kernel routing tables, routed pauses for a brief period to allow any unstable conditions to stabilize. Besides processing incoming RIP packets, routed also checks the internal routing table entries periodically. The metric for any entry that has not been updated for 3 minutes is set to infinity and marked for deletion. The deletion is delayed for 60 seconds so that information about the invalidated route can be distributed throughout the network. A host that acts as an RIP router supplies its routing tables to all directly connected hosts and networks every 30 seconds. Using Gateways In addition to managing routes to directly connected hosts and networks, routed maintains information about distant and external gateways. At startup, routed reads the /etc/gateways file to learn about these gateways. The /etc/gateways file contains information about routes through distant and external gateways to hosts and networks that can be advertised through RIP. These routes are either static routes to specific destinations, or default routes that apply when a static route to a desti- nation is unspecified. Gateways that supply RIP routing information are marked active in the /etc/gateways file. The routed daemons distributes RIP routing information to active gateways; if no RIP routing information is received from the gateway for a period of time, routed deletes the associ- ated route from the routing tables. Gateways that do not exchange RIP routing information are marked passive in the /etc/gateways file. Routed maintains information about passive gateways indefinitely, and includes information about them in any RIP routing information transmitted. Gateways are identified as external to inform routed that another routing process installs the route. Information about external gateways is not maintained in the routing tables. Note that routes through external gateways must be to net- works only. If a logfile is specified, routed writes information about its actions to the specified log file. The log contains information about any changes to the routing tables and a history of recent route change messages sent and received that are related to changed routes. Signals The following signals have the specified effect when sent to the routed process using the kill(1) command: Displays internal routing tables. Broadcasts RIP packets with hop counts set to infinity. Essentially, these signals disable the local host as a router. On a sec- ond SIGHUP, SIGTERM, or SIGQUIT, routed terminates. FILES
Specifies the command path Routes through distant and external gateways Contains the network name database CAUTIONS
The gated and routed daemons should not both be run on the same host, as this may produce unpredictable results. Routes through external gateways must be to networks only. RELATED INFORMATION
Commands: route(8) Daemons: gated(8) delim off routed(8)
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