xref: /freebsd/usr.sbin/rtadvd/rtadvd.8 (revision 4b9d6057)
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30.Dd February 25, 2013
31.Dt RTADVD 8
32.Os
33.Sh NAME
34.Nm rtadvd
35.Nd router advertisement daemon
36.Sh SYNOPSIS
37.Nm
38.Op Fl dDfRs
39.Op Fl c Ar configfile
40.Op Fl C Ar ctlsock
41.Op Fl M Ar ifname
42.Op Fl p Ar pidfile
43.Op Ar interface ...
44.Sh DESCRIPTION
45.Nm
46sends router advertisement packets to the specified
47.Ar interfaces .
48If no interfaces are specified,
49.Nm
50will still run, but will not advertise any routes until interfaces are
51added using
52.Xr rtadvctl 8 .
53.Pp
54The program will daemonize itself on invocation.
55It will then send router advertisement packets periodically, as well
56as in response to router solicitation messages sent by end hosts.
57.Pp
58Router advertisements can be configured on a per-interface basis, as
59described in
60.Xr rtadvd.conf 5 .
61.Pp
62If there is no configuration file entry for an interface,
63or if the configuration file does not exist altogether,
64.Nm
65sets all the parameters to their default values.
66In particular,
67.Nm
68reads all the interface routes from the routing table and advertises
69them as on-link prefixes.
70.Pp
71.Nm
72also watches the routing table.
73If an interface direct route is
74added on an advertising interface and no static prefixes are
75specified by the configuration file,
76.Nm
77adds the corresponding prefix to its advertising list.
78.Pp
79Similarly, when an interface direct route is deleted,
80.Nm
81will start advertising the prefixes with zero valid and preferred
82lifetimes to help the receiving hosts switch to a new prefix when
83renumbering.
84Note, however, that the zero valid lifetime cannot invalidate the
85autoconfigured addresses at a receiving host immediately.
86According to the specification, the host will retain the address
87for a certain period, which will typically be two hours.
88The zero lifetimes rather intend to make the address deprecated,
89indicating that a new non-deprecated address should be used as the
90source address of a new connection.
91This behavior will last for two hours.
92Then
93.Nm
94will completely remove the prefix from the advertising list,
95and succeeding advertisements will not contain the prefix information.
96.Pp
97Moreover, if the status of an advertising interface changes,
98.Nm
99will start or stop sending router advertisements according
100to the latest status.
101.Pp
102The
103.Fl s
104option may be used to disable this behavior;
105.Nm
106will not watch the routing table and the whole functionality described
107above will be suppressed.
108.Pp
109Basically, hosts MUST NOT send Router Advertisement messages at any
110time (RFC 4861, Section 6.2.3).
111However, it would sometimes be useful to allow hosts to advertise some
112parameters such as prefix information and link MTU.
113Thus,
114.Nm
115can be invoked if router lifetime is explicitly set zero on every
116advertising interface.
117.Pp
118The command line options are:
119.Bl -tag -width indent
120.\"
121.It Fl c
122Specify an alternate location,
123.Ar configfile ,
124for the configuration file.
125By default,
126.Pa /etc/rtadvd.conf
127is used.
128.It Fl C
129Specify an alternate location for the control socket used by
130.Xr rtadvctl 8 .
131The default is
132.Pa /var/run/rtadvd.sock .
133.It Fl d
134Print debugging information.
135.It Fl D
136Even more debugging information is printed.
137.It Fl f
138Foreground mode (useful when debugging).
139Log messages will be dumped to stderr when this option is specified.
140.It Fl M
141Specify an interface to join the all-routers site-local multicast group.
142By default,
143.Nm
144tries to join the first advertising interface appearing on the command
145line.
146This option has meaning only with the
147.Fl R
148option, which enables routing renumbering protocol support.
149.It Fl p
150Specify an alternative file in which to store the process ID.
151The default is
152.Pa /var/run/rtadvd.pid .
153.It Fl R
154Accept router renumbering requests.
155If you enable it, certain IPsec setup is suggested for security reasons.
156This option is currently disabled, and is ignored by
157.Nm
158with a warning message.
159.It Fl s
160Do not add or delete prefixes dynamically.
161Only statically configured prefixes, if any, will be advertised.
162.El
163.Pp
164Use
165.Dv SIGHUP
166to reload the configuration file
167.Pa /etc/rtadvd.conf .
168If an invalid parameter is found in the configuration file upon the reload,
169the entry will be ignored and the old configuration will be used.
170When parameters in an existing entry are updated,
171.Nm
172will send Router Advertisement messages with the old configuration but
173zero router lifetime to the interface first, and then start to send a new
174message.
175.Pp
176Use
177.Dv SIGTERM
178to kill
179.Nm
180gracefully.
181In this case,
182.Nm
183will transmit router advertisement with router lifetime 0
184to all the interfaces
185.Pq in accordance with RFC 4861 6.2.5 .
186.Sh FILES
187.Bl -tag -width Pa -compact
188.It Pa /etc/rtadvd.conf
189The default configuration file.
190.It Pa /var/run/rtadvd.pid
191The default process ID file.
192.El
193.Sh EXIT STATUS
194.Ex -std
195.Sh SEE ALSO
196.Xr rtadvd.conf 5 ,
197.Xr rtadvctl 8 ,
198.Xr rtsol 8
199.Rs
200.%A Thomas Narten
201.%A Erik Nordmark
202.%A W. A. Simpson
203.%A Hesham Soliman
204.%T Neighbor Discovery for IP version 6 (IPv6)
205.%R RFC 4861
206.Re
207.Rs
208.%A Thomas Narten
209.%A Erik Nordmark
210.%A W. A. Simpson
211.%T Neighbor Discovery for IP version 6 (IPv6)
212.%R RFC 2461 (obsoleted by RFC 4861)
213.Re
214.Rs
215.%A Richard Draves
216.%T Default Router Preferences and More-Specific Routes
217.%R draft-ietf-ipngwg-router-selection-xx.txt
218.Re
219.Rs
220.%A J. Jeong
221.%A S. Park
222.%A L. Beloeil
223.%A S. Madanapalli
224.%T IPv6 Router Advertisement Options for DNS Configuration
225.%R RFC 6106
226.Re
227.Sh HISTORY
228The
229.Nm
230command first appeared in the WIDE Hydrangea IPv6 protocol stack kit.
231.Sh BUGS
232There used to be some text that recommended users not to let
233.Nm
234advertise Router Advertisement messages on an upstream link to avoid
235undesirable
236.Xr icmp6 4
237redirect messages.
238However, based on the later discussion in the IETF ipng working group,
239all routers should rather advertise the messages regardless of
240the network topology, in order to ensure reachability.
241