xref: /freebsd/usr.sbin/rtadvd/rtadvd.8 (revision 9207b4cff7b8d483f4dd3c62266c2b58819eb7f9)
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31.Dd May 17, 1998
32.Dt RTADVD 8
33.Os
34.Sh NAME
35.Nm rtadvd
36.Nd router advertisement daemon
37.Sh SYNOPSIS
38.Nm
39.Op Fl dDfMRs
40.Op Fl c Ar configfile
41.Ar interface ...
42.Sh DESCRIPTION
43.Nm
44sends router advertisement packets to the specified
45.Ar interfaces .
46.Pp
47The program will daemonize itself on invocation.
48It will then send router advertisement packets periodically, as well
49as in response to router solicitation messages sent by end hosts.
50.Pp
51Router advertisements can be configured on a per-interface basis, as
52described in
53.Xr rtadvd.conf 5 .
54.Pp
55If there is no configuration file entry for an interface,
56or if the configuration file does not exist altogether,
57.Nm
58sets all the parameters to their default values.
59In particular,
60.Nm
61reads all the interface routes from the routing table and advertises
62them as on-link prefixes.
63.Pp
64.Nm
65also watches the routing table.
66By default, if an interface direct route is
67added/deleted on an advertising interface and no static prefixes are
68specified by the configuration file,
69.Nm
70adds/deletes the corresponding prefix to/from its advertising list,
71respectively.
72The
73.Fl s
74option may be used to disable this behavior.
75Moreover, if the status of an advertising interface changes,
76.Nm
77will start or stop sending router advertisements according
78to the latest status.
79.Pp
80Basically, hosts MUST NOT send Router Advertisement messages at any
81time (RFC 2461, Section 6.2.3).
82However, it would sometimes be useful to allow hosts to advertise some
83parameters such as prefix information and link MTU.
84Thus,
85.Nm
86can be invoked if router lifetime is explicitly set zero on every
87advertising interface.
88.Pp
89The command line options are:
90.Bl -tag -width indent
91.\"
92.It Fl c
93Specify an alternate location,
94.Ar configfile ,
95for the configuration file.
96By default,
97.Pa /etc/rtadvd.conf
98is used.
99.It Fl d
100Print debugging information.
101.It Fl D
102Even more debugging information is printed.
103.It Fl f
104Foreground mode (useful when debugging).
105.It Fl M
106Specify an interface to join the all-routers site-local multicast group.
107By default,
108.Nm
109tries to join the first advertising interface appeared in the command
110line.
111This option has meaning only with the
112.Fl R
113option, which enables routing renumbering protocol support.
114.\".It Fl m
115.\"Enables mobile IPv6 support.
116.\"This changes the content of router advertisement option, as well as
117.\"permitted configuration directives.
118.It Fl R
119Accept router renumbering requests.
120If you enable it, certain IPsec setup is suggested for security reasons.
121On KAME-based systems,
122.Xr rrenumd 8
123generates router renumbering request packets.
124This option is currently disabled, and is ignored by
125.Nm
126with a warning message.
127.It Fl s
128Do not add or delete prefixes dynamically.
129Only statically configured prefixes, if any, will be advertised.
130.El
131.Pp
132Upon receipt of signal
133.Dv SIGUSR1 ,
134.Nm
135will dump the current internal state into
136.Pa /var/run/rtadvd.dump .
137.Pp
138Use
139.Dv SIGTERM
140to kill
141.Nm
142gracefully.
143In this case,
144.Nm
145will transmit router advertisement with router lifetime 0
146to all the interfaces
147(in accordance with RFC2461 6.2.5).
148.Sh DIAGNOSTICS
149.Ex -std
150.Sh FILES
151.Bl -tag -width Pa -compact
152.It Pa /etc/rtadvd.conf
153The default configuration file.
154.It Pa /var/run/rtadvd.pid
155contains the pid of the currently running
156.Nm .
157.It Pa /var/run/rtadvd.dump
158in which
159.Nm
160dumps its internal state.
161.El
162.Sh SEE ALSO
163.Xr rtadvd.conf 5 ,
164.Xr rrenumd 8 ,
165.Xr rtsol 8
166.Sh HISTORY
167The
168.Nm
169command first appeared in WIDE Hydrangea IPv6 protocol stack kit.
170.Sh CAVEAT
171There used to be some text that recommended users not to let
172.Nm
173advertise Router Advertisement messages on an upstream link to avoid
174undesirable
175.Xr icmp6 4
176redirect messages.
177However, based on the later discussion in the IETF ipng working group,
178all routers should rather advertise the messages regardless of
179the network topology, in order to ensure reachability.
180