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28 .\" @(#)rwhod.8 8.2 (Berkeley) 12/11/93
36 .Nd system status server
46 utility is the server which maintains the database used by the
51 Its operation is predicated on the ability to
55 messages on a network.
59 utility operates as both a producer and consumer of status information,
62 (listen mode) option is specified, in which case
63 it acts as a consumer only.
64 As a producer of information it periodically
65 queries the state of the system and constructs
66 status messages which are broadcasted or multicasted on a network.
67 As a consumer of information, it listens for other
69 servers' status messages, validating them, then recording
70 them in a collection of files located in the directory
73 The following options are available:
74 .Bl -tag -width indent
76 Enable insecure mode, which causes
78 to ignore the source port on incoming packets.
83 This is useful if you do not wish to keep dial on demand
84 interfaces permanently active.
86 Enable listen mode, which causes
88 to not broadcast any information.
89 This allows you to monitor other machines'
91 information, without broadcasting your own.
95 to use IP multicast (instead of
96 broadcast) on all interfaces that have
97 the IFF_MULTICAST flag set in their "ifnet" structs
98 (excluding the loopback interface).
100 reports are sent with a time-to-live of 1, to prevent
101 forwarding beyond the directly-connected subnet(s).
105 argument is supplied with the
109 will send IP multicast datagrams with a
112 via a SINGLE interface rather
115 must be between 0 and
116 32 (or MAX_MULTICAST_SCOPE).
123 specifies transmission on one interface only.
129 argument, the program accepts multicast
131 reports from all multicast-capable interfaces.
134 argument is given, it accepts multicast reports from only one interface, the
135 one on which reports are sent (which may be controlled via the host's routing
139 option, the program accepts broadcast or
140 unicast reports from all interfaces.
141 Thus, this program will hear the
142 reports of old, non-multicasting
144 but, if multicasting is used,
147 will not hear the reports generated by this program.
150 The server transmits and receives messages at the port indicated
151 in the ``who'' service specification; see
153 The messages sent and received, are of the form:
154 .Bd -literal -offset indent
156 char out_line[8]; /* tty name */
157 char out_name[8]; /* user id */
158 long out_time; /* time on */
167 char wd_hostname[32];
171 struct outmp we_utmp;
173 } wd_we[1024 / sizeof (struct whoent)];
177 All fields are converted to network byte order prior to
179 The load averages are as calculated by the
181 program, and represent load averages over the 5, 10, and 15 minute
182 intervals prior to a server's transmission; they are multiplied by 100
183 for representation in an integer.
185 included is that returned by the
187 system call, with any trailing domain name omitted.
188 The array at the end of the message contains information about
189 the users logged in to the sending machine.
191 includes the contents of the entry from the user accounting database
192 for each non-idle terminal line and a value indicating the
193 time in seconds since a character was last received on the terminal line.
195 Messages received by the
197 server are discarded unless they originated at an
201 option was specified.
202 In addition, if the host's name, as specified
203 in the message, contains any unprintable
206 message is discarded.
207 Valid messages received by
209 are placed in files named
213 These files contain only the most recent message, in the
214 format described above.
216 Status messages are generated approximately once every
223 .Pa /boot/kernel/kernel
224 every 30 minutes to guard against
225 the possibility that this file is not the system
226 image currently operating.
236 Status information should be sent only upon request rather than continuously.
237 People often interpret the server dying
238 or network communication failures
239 as a machine going down.