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RRRROOOOUUUUTTTTEEEEDDDD((((1111MMMM)))) RRRROOOOUUUUTTTTEEEEDDDD((((1111MMMM)))) NNNNAAAAMMMMEEEE routed - network RIP and router discovery routing daemon SSSSYYYYNNNNOOOOPPPPSSSSIIIISSSS ////uuuussssrrrr////eeeettttcccc////rrrroooouuuutttteeeedddd [----ssssqqqqddddgggghhhhmmmmppppAAAAttttvvvv] [----TTTT _t_r_a_c_e_f_i_l_e] [----FFFF _n_e_t[/_m_a_s_k][,_m_e_t_r_i_c]] [----PPPP _p_a_r_m_s] DDDDEEEESSSSCCCCRRRRIIIIPPPPTTTTIIIIOOOONNNN RRRRoooouuuutttteeeedddd is a dameon invoked at boot time to manage the network routing tables. It uses Routing Information Protocol, RIPv1 (RFC 1058), RIPv2 (RFC 1723), and Internet Router Discovery Protocol (RFC 1256) to maintain the kernel routing table. The RIPv1 protocol is based on the reference 4.3BSD daemon. It listens on the _u_d_p(7P) socket for the _r_o_u_t_e service (see _s_e_r_v_i_c_e_s(4)) for Routing Information Protocol packets. It also sends and receives multicast Router Discovery ICMP messages. If the host is a router, rrrroooouuuutttteeeedddd periodically supplies copies of its routing tables to any directly connected hosts and networks. It also advertise or solicits default routes using Router Discovery ICMP messages. When started (or when a network interface is later turned on), rrrroooouuuutttteeeedddd uses an AF_ROUTE address family facility to find those directly connected interfaces configured into the system and marked "up". It adds necessary routes for the interfaces to the kernel routing table. Soon after being first started, and provided there is at least one interface on which RIP has not been disabled, rrrroooouuuutttteeeedddd deletes all pre-existing non-static routes in kernel table. Static routes in the kernel table are preserved and included in RIP responses if they have a valid RIP metric (see rrrroooouuuutttteeee(1M)). If more than one interface is present (not counting the loopback interface), it is assumed that the host should forward packets among the connected networks. After transmitting a RIP rrrreeeeqqqquuuueeeesssstttt and Router Discovery Advertisements or Solicitations on a new interface, the daemon enters a loop, listening for RIP request and response and Router Discovery packets from other hosts. When a _r_e_q_u_e_s_t packet is received, _r_o_u_t_e_d formulates a reply based on the information maintained in its internal tables. The _r_e_s_p_o_n_s_e packet generated contains a list of known routes, each marked with a "hop count" metric (a count of 16 or greater is considered "infinite"). Advertised metrics reflect the metric associated with interface (see iiiiffffccccoooonnnnffffiiiigggg(1M)), so setting the metric on an interface is an effective way to steer traffic. Responses do not include routes with a first hop on the requesting network to implement in part _s_p_l_i_t-_h_o_r_i_z_o_n. Requests from query programs such as rrrrttttqqqquuuueeeerrrryyyy(1M) are answered with the complete table. PPPPaaaaggggeeee 1111 RRRROOOOUUUUTTTTEEEEDDDD((((1111MMMM)))) RRRROOOOUUUUTTTTEEEEDDDD((((1111MMMM)))) The routing table maintained by the daemon includes space for several gateways for each destination to speed recovery from a failing router. RIP _r_e_s_p_o_n_s_e packets received are used to update the routing tables provided they are from one of the several currently recognized gateways or advertise a better metric than at least one of the existing gateways. When an update is applied, rrrroooouuuutttteeeedddd records the change in its own tables and updates the kernel routing table if the best route to the destination changes. The change in the kernel routing table is reflected in the next batch of _r_e_s_p_o_n_s_e packets sent. If the next response is not scheduled for a while, a _f_l_a_s_h _u_p_d_a_t_e response containing only recently changed routes is sent. In addition to processing incoming packets, rrrroooouuuutttteeeedddd also periodically checks the routing table entries. If an entry has not been updated for 3 minutes, the entry's metric is set to infinity and marked for deletion. Deletions are delayed until the route has been advertised with an infinite metric to insure the invalidation is propagated throughout the local internet. This is a form of _p_o_i_s_o_n _r_e_v_e_r_s_e. Routes in the kernel table that are added or changed as a result of ICMP Redirect messages are deleted after a while to minimize _b_l_a_c_k-_h_o_l_e_s. When a TCP connection suffers a timeout, the kernel tells rrrroooouuuutttteeeedddd, which deletes all redirected routes through the gateway involved, advances the age of all RIP routes through the gateway to allow an alternate to be chosen, and advances of the age of any relevant Router Discovery Protocol default routes. Hosts acting as internetwork routers gratuitously supply their routing tables every 30 seconds to all directly connected hosts and networks. These RIP responses are sent to the broadcast address on nets that support broadcasting, to the destination address on point-to-point links, and to the router's own address on other networks. If RIPv2 is enabled, multicast packets are sent on interfaces that support multicasting. If no response is received on a remote interface, if there are errors while sending responses, or if there are more errors than input or output (see nnnneeeettttssssttttaaaatttt(1M)), then the cable or some other part of the interface is assumed to be disconnected or broken, and routes are adjusted appropriately. The _I_n_t_e_r_n_e_t _R_o_u_t_e_r _D_i_s_c_o_v_e_r_y _P_r_o_t_o_c_o_l is handled similarly. When the daemon is supplying RIP routes, it also listens for Router Discovery Solicitations and sends Advertisements. When it is quiet and listening to other RIP routers, it sends Solicitations and listens for Advertisements. If it receives a good Advertisement and it is not multi-homed, it stops listening for broadcast or multicast RIP responses. It tracks several advertising routers to speed recovery when the currently chosen router dies. If all discovered routers disappear, the daemon resumes listening to RIP responses. It continues listen to RIP while using Router Discovery if multi-homed to ensure all interfaces are used. PPPPaaaaggggeeee 2222 RRRROOOOUUUUTTTTEEEEDDDD((((1111MMMM)))) RRRROOOOUUUUTTTTEEEEDDDD((((1111MMMM)))) The Router Discovery standard requires that advertisements have a default "lifetime" of 30 minutes. That means should something happen, a client can be without a good route for 30 minutes. It is a good idea to reduce the default to 45 seconds using "----PPPP _r_d_i_s_c__i_n_t_e_r_v_a_l=_4_5" on the command line or "rrrrddddiiiisssscccc____iiiinnnntttteeeerrrrvvvvaaaallll====44445555" in the /_e_t_c/_g_a_t_e_w_a_y_s file. While using Router Discovery (which happens by default when the system has a single network interface and a Router Discovery Advertisement is received), there is a single default route and a variable number of redirected host routes in the kernel table. On a host with more than one network interface, this default route will be via only one of the interfaces. Thus, multi-homed hosts running with ----qqqq might need nnnnoooo____rrrrddddiiiisssscccc described below. See the ppppmmmm____rrrrddddiiiisssscccc facility described below to support "legacy" systems that can handle neither RIPv2 nor Router Discovery. By default, neither Router Discovery advertisements nor solicitations are sent over point to point links (e.g. PPP). The netmask associated with point-to-point links (such as SLIP or PPP, with the IFF_POINTOPOINT flag) is used by rrrroooouuuutttteeeedddd to infer the netmask used by the remote system when RIPv1 is used. RRRRoooouuuutttteeeedddd is started during system initialization from /_e_t_c/_i_n_i_t._d/_n_e_t_w_o_r_k using site-dependent options and arguments in the file /_e_t_c/_c_o_n_f_i_g/_r_o_u_t_e_d._o_p_t_i_o_n_s. The options are: ----ssss this option forces rrrroooouuuutttteeeedddd to supply routing information. This is the default if multiple network interfaces are present on which RIP or Router Discovery have not been disabled, and if the kernel switch ipforwarding=1. ----qqqq is the opposite of the ----ssss option. This is the default when only one interface is present. ----dddd Do not run in the background. This option is meant for interactive use - do not put it in the _r_o_u_t_e_d._o_p_t_i_o_n_s file. ----gggg This flag is used on internetwork routers to offer a route to the "default" destination. It is equivalent to "----FFFF _0/_0,_1" and is present mostly for historical reasons. A better choice is "----PPPP _p_m__r_d_i_s_c" on the command line or ppppmmmm____rrrrddddiiiisssscccc in the /_e_t_c/_g_a_t_e_w_a_y_s file. since a larger metric will be used, reducing the spread of the potentially dangerous default route. This is typically used on a gateway to the Internet, or on a gateway that uses another routing protocol whose routes are not reported to other local routers. Notice that because a metric of 1 is used, this feature is dangerous. It is more commonly accidentally used to create chaos with routing loop than to solve problems. PPPPaaaaggggeeee 3333 RRRROOOOUUUUTTTTEEEEDDDD((((1111MMMM)))) RRRROOOOUUUUTTTTEEEEDDDD((((1111MMMM)))) ----hhhh This causes host or point-to-point routes to not be advertised, provided there is a network route going the same direction. That is a limited kind of aggregation. This option is useful on gateways to ethernets that have other gateway machines connected with point-to- point links such as SLIP. ----mmmm This causes the machine to advertise a host or point-to-point route to its primary interface. It is useful on multi-homed machines such as NFS servers. This option should not be used except when the cost of the host routes it generates is justified by the popularity of the server. It is effective only when the machine is supplying routing information, because there is more than one interface. The ----mmmm option overrides the ----qqqq option to the limited extent of advertising the host route. ----AAAA do not ignore RIPv2 authentication if we do not care about RIPv2 authentication. This option is required for conformance with RFC 1723, However, it makes no sense and breaks using RIP as a discovery protocol to ignore all RIPv2 packets that carry authentication when this machine does not care about authentication. ----tttt increases the debugging level, which causes more information to be logged on the tracefile specified with ----TTTT or standard out. The debugging level can be increased or decreased with the SSSSIIIIGGGGUUUUSSSSRRRR1111 or SSSSIIIIGGGGUUUUSSSSRRRR2222 signals, or with the rrrrttttqqqquuuueeeerrrryyyy command. ----vvvv displays and logs the version of daemon. ----TTTT _t_r_a_c_e_f_i_l_e increases the debugging level to at least 1 and causes debugging information to be appended to the trace file. Note that because of security concerns, it is wisest to not run rrrroooouuuutttteeeedddd routinely with tracing directed to a file. ----FFFF _n_e_t[/_m_a_s_k][=_m_e_t_r_i_c] minimize routes in transmissions via interfaces with addresses that match _n_e_t/_m_a_s_k, and synthesizes a default route to this machine with the _m_e_t_r_i_c. The intent is to reduce RIP traffic on slow, point-to- point links such as PPP links by replacing many large UDP packets of RIP information with a single, small packet containing a "fake" default route. If _m_e_t_r_i_c is absent, a value of 14 is assumed to limit the spread of the "fake" default route. This is a dangerous feature that when used carelessly can cause routing loops. Notice also that more than one interface can match the specified network number and mask. See also ----gggg. ----PPPP _p_a_r_m_s is equivalent to adding the parameter line _p_a_r_m_s to the /_e_t_c/_g_a_t_e_w_a_y_s file. PPPPaaaaggggeeee 4444 RRRROOOOUUUUTTTTEEEEDDDD((((1111MMMM)))) RRRROOOOUUUUTTTTEEEEDDDD((((1111MMMM)))) Any other argument supplied is interpreted as the name of a file in which _r_o_u_t_e_d's actions should be logged. It is better to use ----TTTT instead of appending the name of the trace file to the command. rrrroooouuuutttteeeedddd also supports the notion of "distant" _p_a_s_s_i_v_e or _a_c_t_i_v_e gateways. When rrrroooouuuutttteeeedddd is started, it reads the file /_e_t_c/_g_a_t_e_w_a_y_s to find such distant gateways which may not be located using only information from a routing socket, to discover if some of the local gateways are _p_a_s_s_i_v_e, and to obtain other parameters. Gateways specified in this manner should be marked passive if they are not expected to exchange routing information, while gateways marked active should be willing to exchange RIP packets. Routes through _p_a_s_s_i_v_e gateways are installed in the kernel's routing tables once upon startup and are not included in transmitted RIP responses. Distant active gateways are treated like network interfaces. RIP responses are sent to the distant _a_c_t_i_v_e gateway. If no responses are received, the associated route is deleted from the kernel table and RIP responses advertised via other interfaces. If the distant gateway resumes sending RIP responses, the associated route is restored. Such gateways can be useful on media that do not support broadcasts or multicasts but otherwise act like classic shared media like Ethernets such as some ATM networks. One can list all RIP routers reachable on the ATM network in /_e_t_c/_g_a_t_e_w_a_y_s with a series of "host" lines. Note that it is usually desirable to use RIPv2 in such situations to avoid generating lists of inferred host routes. Gateways marked _e_x_t_e_r_n_a_l 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 indicate that another routing process will install such a route if necessary, and that alternate routes to that destination should not be installed by rrrroooouuuutttteeeedddd. Such entries are only required when both routers may learn of routes to the same destination. The /_e_t_c/_g_a_t_e_w_a_y_s file is comprised of a series of lines, each in one of the following two formats or consist of parameters described later. Blank lines and lines starting with '#' are comments. nnnneeeetttt _N_n_a_m_e[/_m_a_s_k] ggggaaaatttteeeewwwwaaaayyyy _G_n_a_m_e mmmmeeeettttrrrriiiicccc _v_a_l_u_e {ppppaaaassssssssiiiivvvveeee|aaaaccccttttiiiivvvveeee|eeeexxxxtttteeeerrrrnnnnaaaallll} hhhhoooosssstttt _H_n_a_m_e ggggaaaatttteeeewwwwaaaayyyy _G_n_a_m_e mmmmeeeettttrrrriiiicccc _v_a_l_u_e {ppppaaaassssssssiiiivvvveeee|aaaaccccttttiiiivvvveeee|eeeexxxxtttteeeerrrrnnnnaaaallll} _N_n_a_m_e or _H_n_a_m_e is the name of the destination network or host. It may be a symbolic network name or an Internet address specified in "dot" notation (see _i_n_e_t(3N)). (If it is a name, then it must either be defined in /_e_t_c/_n_e_t_w_o_r_k_s or /_e_t_c/_h_o_s_t_s, or name service must have been started before rrrroooouuuutttteeeedddd.) _m_a_s_k is an optional number between 1 and 32 indicating the netmask associated with _N_n_a_m_e. _G_n_a_m_e is the name or address of the gateway to which RIP responses should be forwarded. _V_a_l_u_e is the hop count to the destination host or network. "hhhhoooosssstttt _h_n_a_m_e" is equivalent to "nnnneeeetttt _n_n_a_m_e/_3_2". PPPPaaaaggggeeee 5555 RRRROOOOUUUUTTTTEEEEDDDD((((1111MMMM)))) RRRROOOOUUUUTTTTEEEEDDDD((((1111MMMM)))) One of the keywords ppppaaaassssssssiiiivvvveeee, aaaaccccttttiiiivvvveeee or eeeexxxxtttteeeerrrrnnnnaaaallll must be present to indicate whether the gateway should be treated as _p_a_s_s_i_v_e or _a_c_t_i_v_e (as described above), or whether the gateway is _e_x_t_e_r_n_a_l to the scope of the RIP protocol. As can be seen when debugging is turned on with such lines create psuedo-interfaces. To set parameters for remote or external interfaces, a line starting with iiiiffff====aaaalllliiiiaaaassss((((HHHHnnnnaaaammmmeeee)))), iiiiffff====rrrreeeemmmmooootttteeee((((HHHHnnnnaaaammmmeeee)))), etc. should be used. Lines that start with neither "net" nor "host" must consist of one or more of the following parameter settings, separated by commas or blanks: iiiiffff====_i_f_n_a_m_e indicates that the other parameters on the line apply to the interface name _i_f_n_a_m_e. ssssuuuubbbbnnnneeeetttt====_n_n_a_m_e[/_m_a_s_k][,_m_e_t_r_i_c] advertises a route to network _n_n_a_m_e with mask _m_a_s_k and the supplied metric (default 1). This is useful for filling "holes" in CIDR allocations. This parameter must appear by itself on a line. The network number must specify a full, 32-bit value, as in 192.0.2.0 instead of 192.0.2. Do not use this feature unless necessary. It is dangerous. rrrriiiippppvvvv1111____mmmmaaaasssskkkk====_n_n_a_m_e/_m_a_s_k_1,_m_a_s_k_2 specifies that netmask of the network of which _n_n_a_m_e/_m_a_s_k_1 is a subnet should be _m_a_s_k_2. For example _r_i_p_v_1__m_a_s_k=_1_9_2._0._2._1_6/_2_8,_2_7 marks 192.0.2.16/28 as a subnet of 192.0.2.0/28 instead of 192.0.2.0/24. ppppaaaasssssssswwwwdddd=_X_X_X_1[|_K_e_y_I_D[_s_t_a_r_t|_s_t_o_p]] specifies a RIPv2 cleartext password that will be included on all RIPv2 responses sent, and checked on all RIPv2 responses received. Any blanks, tab characters, commas, or '#', '|', or NULL characters in the password must be escaped with a backslash (\). The common escape sequences \n, \r, \t, \b, and \xxx have their usual meanings. The _K_e_y_I_D must be unique but is ignored for cleartext passwords. If present, _s_t_a_r_t and _s_t_o_p are timestamps in the form year/month/day@hour:minute. They specify when the password is valid. The valid password with the most future is used on output packets, unless all passwords have expired, in which case the password that expired most recently is used, or unless no passwords are valid yet, in which case no password is output. Incoming packets can carry any password that is valid, will be valid within 24 hours, or that was valid within 24 hours. To protect the secrets, the password settings are valid only in the /_e_t_c/_g_a_t_e_w_a_y_s file and only when that file is readable only by UID 0. PPPPaaaaggggeeee 6666 RRRROOOOUUUUTTTTEEEEDDDD((((1111MMMM)))) RRRROOOOUUUUTTTTEEEEDDDD((((1111MMMM)))) mmmmdddd5555____ppppaaaasssssssswwwwdddd=_X_X_X_1|_K_e_y_I_D[_s_t_a_r_t|_s_t_o_p] specifies a RIPv2 MD5 password. Except that a _K_e_y_I_D is required, this keyword is similar to ppppaaaasssssssswwwwdddd. nnnnoooo____aaaagggg turns off aggregation of subnets in RIPv1 and RIPv2 responses. nnnnoooo____ssssuuuuppppeeeerrrr____aaaagggg turns off aggregation of networks into supernets in RIPv2 responses. ppppaaaassssssssiiiivvvveeee marks the interface to not be advertised in updates sent via other interfaces, and turns off all RIP and router discovery through the interface. nnnnoooo____rrrriiiipppp disables all RIP processing on the specified interface. If no interfaces are allowed to process RIP packets, rrrroooouuuutttteeeedddd acts purely as a router discovery daemon. Note that turning off RIP without explicitly turning on router discovery advertisements with rrrrddddiiiisssscccc____aaaaddddvvvv or ----ssss causes rrrroooouuuutttteeeedddd to act as a client router discovery daemon, not advertising. nnnnoooo____rrrriiiipppp____mmmmccccaaaasssstttt causes RIPv2 packets to be broadcast instead of multicast. nnnnoooo____rrrriiiippppvvvv1111____iiiinnnn causes RIPv1 received responses to be ignored. nnnnoooo____rrrriiiippppvvvv2222____iiiinnnn causes RIPv2 received responses to be ignored. rrrriiiippppvvvv2222____oooouuuutttt turns off RIPv1 output and causes RIPv2 advertisements to be multicast when possible. rrrriiiippppvvvv2222 is equivalent to nnnnoooo____rrrriiiippppvvvv1111____iiiinnnn and nnnnoooo____rrrriiiippppvvvv1111____oooouuuutttt. nnnnoooo____rrrrddddiiiisssscccc disables the Internet Router Discovery Protocol. nnnnoooo____ssssoooolllliiiicccciiiitttt disables the transmission of Router Discovery Solicitations. sssseeeennnndddd____ssssoooolllliiiicccciiiitttt specifies that Router Discovery solicitations should be sent, even on point-to-point links, which by default only listen to Router Discovery messages. PPPPaaaaggggeeee 7777 RRRROOOOUUUUTTTTEEEEDDDD((((1111MMMM)))) RRRROOOOUUUUTTTTEEEEDDDD((((1111MMMM)))) nnnnoooo____rrrrddddiiiisssscccc____aaaaddddvvvv disables the transmission of Router Discovery Advertisements rrrrddddiiiisssscccc____aaaaddddvvvv specifies that Router Discovery Advertisements should be sent, even on point-to-point links, which by default only listen to Router Discovery messages bbbbccccaaaasssstttt____rrrrddddiiiisssscccc specifies that Router Discovery packets should be broadcast instead of multicast. rrrrddddiiiisssscccc____pppprrrreeeeffff=_N sets the preference in Router Discovery Advertisements to the optionally signed integer _N. The default preference is 0. Default routes with smaller or more negative preferences are preferred by clients. rrrrddddiiiisssscccc____iiiinnnntttteeeerrrrvvvvaaaallll=_N sets the nominal interval with which Router Discovery Advertisements are transmitted to _N seconds and their lifetime to 3*_N. ffffaaaakkkkeeee____ddddeeeeffffaaaauuuulllltttt====_m_e_t_r_i_c has an identical effect to "----FFFF net/mask,_m_e_t_r_i_c" with the network and mask coming from the specified interface. ppppmmmm____rrrrddddiiiisssscccc is similar to ffffaaaakkkkeeee____ddddeeeeffffaaaauuuulllltttt. When RIPv2 routes are multicast, so that RIPv1 listeners cannot receive them, this feature causes a RIPv1 default route to be broadcast to RIPv1 listeners. Unless modified with ffffaaaakkkkeeee____ddddeeeeffffaaaauuuulllltttt, the default route is broadcast with a metric of 14. That serves as a "poor man's router discovery" protocol. ttttrrrruuuusssstttt____ggggaaaatttteeeewwwwaaaayyyy=_r_n_a_m_e[|_n_e_t_1/_m_a_s_k_1|_n_e_t_2/_m_a_s_k_2|...] causes RIP packets from that router and other routers named in other ttttrrrruuuusssstttt____ggggaaaatttteeeewwwwaaaayyyy keywords to be accepted, and packets from other routers to be ignored. If networks are specified, then routes to other networks will be ignored from that router. rrrreeeeddddiiiirrrreeeecccctttt____ooookkkk causes RIP to allow ICMP Redirect messages when the system is acting as a router and forwarding packets. Otherwise, ICMP Redirect messages are overridden. FFFFIIIILLLLEEEESSSS /etc/gateways for distant gateways /etc/config/routed.options Site-dependent options PPPPaaaaggggeeee 8888 RRRROOOOUUUUTTTTEEEEDDDD((((1111MMMM)))) RRRROOOOUUUUTTTTEEEEDDDD((((1111MMMM)))) SEE ALSO gated(1M), udp(7P), icmp(7P), rtquery(1M) BBBBUUUUGGGGSSSS It does not always detect unidirectional failures in network interfaces (e.g., when the output side fails). PPPPaaaaggggeeee 9999 
