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1 | .\" Copyright (c) 1986 Regents of the University of California. |
2 | .\" All rights reserved. The Berkeley software License Agreement | |
3 | .\" specifies the terms and conditions for redistribution. | |
4 | .\" | |
5 | .\" @(#)XNSrouted.8 6.1 (Berkeley) %G% | |
6 | .\" | |
7 | .TH XNSROUTED 8C "" | |
8 | .UC 6 | |
9 | .SH NAME | |
10 | XNSrouted \- NS Routing Information Protocol daemon | |
11 | .SH SYNOPSIS | |
12 | .B /etc/XNSrouted | |
13 | [ | |
14 | .B \-s | |
15 | ] [ | |
16 | .B \-q | |
17 | ] [ | |
18 | .B \-t | |
19 | ] [ | |
20 | .I logfile | |
21 | ] | |
22 | .SH DESCRIPTION | |
23 | .I XNSrouted | |
24 | is invoked at boot time to manage the Xerox NS routing tables. | |
25 | The NS routing daemon uses the Xerox NS Routing | |
26 | Information Protocol in maintaining up to date kernel routing | |
27 | table entries. | |
28 | .PP | |
29 | In normal operation | |
30 | .I XNSrouted | |
31 | listens | |
32 | for routing information packets. If the host is connected to | |
33 | multiple NS networks, it periodically supplies copies | |
34 | of its routing tables to any directly connected hosts | |
35 | and networks. | |
36 | .PP | |
37 | When | |
38 | .I XNSrouted | |
39 | is started, it uses the SIOCGIFCONF | |
40 | .I ioctl | |
41 | to find those | |
42 | directly connected interfaces configured into the | |
43 | system and marked ``up'' (the software loopback interface | |
44 | is ignored). If multiple interfaces | |
45 | are present, it is assumed the host will forward packets | |
46 | between networks. | |
47 | .I XNSrouted | |
48 | then transmits a | |
49 | .I request | |
50 | packet on each interface (using a broadcast packet if | |
51 | the interface supports it) and enters a loop, listening | |
52 | for | |
53 | .I request | |
54 | and | |
55 | .I response | |
56 | packets from other hosts. | |
57 | .PP | |
58 | When a | |
59 | .I request | |
60 | packet is received, | |
61 | .I XNSrouted | |
62 | formulates a reply based on the information maintained in its | |
63 | internal tables. The | |
64 | .I response | |
65 | packet generated contains a list of known routes, each marked | |
66 | with a ``hop count'' metric (a count of 16, or greater, is | |
67 | considered ``infinite''). The metric associated with each | |
68 | route returned provides a metric | |
69 | .IR "relative to the sender" . | |
70 | .PP | |
71 | .I Response | |
72 | packets received by | |
73 | .I XNSrouted | |
74 | are used to update the routing tables if one of the following | |
75 | conditions is satisfied: | |
76 | .TP | |
77 | (1) | |
78 | No routing table entry exists for the destination network | |
79 | or host, and the metric indicates the destination is ``reachable'' | |
80 | (i.e. the hop count is not infinite). | |
81 | .TP | |
82 | (2) | |
83 | The source host of the packet is the same as the router in the | |
84 | existing routing table entry. That is, updated information is | |
85 | being received from the very internetwork router through which | |
86 | packets for the destination are being routed. | |
87 | .TP | |
88 | (3) | |
89 | The existing entry in the routing table has not been updated for | |
90 | some time (defined to be 90 seconds) and the route is at least | |
91 | as cost effective as the current route. | |
92 | .TP | |
93 | (4) | |
94 | The new route describes a shorter route to the destination than | |
95 | the one currently stored in the routing tables; the metric of | |
96 | the new route is compared against the one stored in the table | |
97 | to decide this. | |
98 | .PP | |
99 | When an update is applied, | |
100 | .I XNSrouted | |
101 | records the change in its internal tables and generates a | |
102 | .I response | |
103 | packet to all directly connected hosts and networks. | |
104 | .I Routed | |
105 | waits a short period | |
106 | of time (no more than 30 seconds) before modifying the kernel's | |
107 | routing tables to allow possible unstable situations to settle. | |
108 | .PP | |
109 | In addition to processing incoming packets, | |
110 | .I XNSrouted | |
111 | also periodically checks the routing table entries. | |
112 | If an entry has not been updated for 3 minutes, the entry's metric | |
113 | is set to infinity and marked for deletion. Deletions are delayed | |
114 | an additional 60 seconds to insure the invalidation is propagated | |
115 | to other routers. | |
116 | .PP | |
117 | Hosts acting as internetwork routers gratuitously supply their | |
118 | routing tables every 30 seconds to all directly connected hosts | |
119 | and networks. | |
120 | .PP | |
121 | Supplying the | |
122 | .B \-s | |
123 | option forces | |
124 | .I XNSrouted | |
125 | to supply routing information whether it is acting as an internetwork | |
126 | router or not. | |
127 | The | |
128 | .B \-q | |
129 | option is the opposite of the | |
130 | .B \-s | |
131 | option. If the | |
132 | .B \-t | |
133 | option is specified, all packets sent or received are | |
134 | printed on the standard output. In addition, | |
135 | .I XNSrouted | |
136 | will not divorce itself from the controlling terminal | |
137 | so that interrupts from the keyboard will kill the process. | |
138 | Any other argument supplied is interpreted as the name | |
139 | of file in which | |
140 | .IR XNSrouted 's | |
141 | actions should be logged. This log contains information | |
142 | about any changes to the routing tables and a history of | |
143 | recent messages sent and received which are related to | |
144 | the changed route. | |
145 | .SH "SEE ALSO" | |
146 | ``Internet Transport Protocols'', XSIS 028112, Xerox System Integration | |
147 | Standard. | |
148 | .br | |
149 | idp(4P) |