1in.rwhod(1M) System Administration Commands in.rwhod(1M)
2
3
4
6 in.rwhod, rwhod - system status server
7
9 /usr/sbin/in.rwhod [-m [ttl]]
10
11
13 in.rwhod is the server which maintains the database used by the rwho(1)
14 and ruptime(1) programs. Its operation is predicated on the ability to
15 broadcast or multicast messages on a network.
16
17
18 in.rwhod operates as both a producer and consumer of status informa‐
19 tion. As a producer of information it periodically queries the state of
20 the system and constructs status messages which are broadcast or multi‐
21 cast on a network. As a consumer of information, it listens for other
22 in.rwhod servers' status messages, validating them, then recording them
23 in a collection of files located in the directory /var/spool/rwho.
24
25
26 The rwho server transmits and receives messages at the port indicated
27 in the rwho service specification, see services(4). The messages sent
28 and received are defined in /usr/include/protocols/rwhod.h and are of
29 the form:
30
31 struct outmp {
32 char out_line[8]; /* tty name */
33 char out_name[8]; /* user id */
34 long out_time; /* time on */
35 };
36 struct whod {
37 char wd_vers;
38 char wd_type;
39 char wd_fill[2];
40 int wd_sendtime;
41 int wd_recvtime;
42 char wd_hostname[32];
43 int wd_loadav[3];
44 int wd_boottime;
45 struct whoent {
46 struct outmp we_utmp;
47 int we_idle;
48 } wd_we[1024 / sizeof (struct whoent)];
49 };
50
51
52
53
54 All fields are converted to network byte order prior to transmission.
55 The load averages are as calculated by the w(1) program, and represent
56 load averages over the 1, 5, and 15 minute intervals prior to a
57 server's transmission. The host name included is that returned by the
58 uname(2) system call. The array at the end of the message contains
59 information about the users who are logged in to the sending machine.
60 This information includes the contents of the utmpx(4) entry for each
61 non-idle terminal line and a value indicating the time since a charac‐
62 ter was last received on the terminal line.
63
64
65 Messages received by the rwho server are discarded unless they origi‐
66 nated at a rwho server's port. In addition, if the host's name, as
67 specified in the message, contains any unprintable ASCII characters,
68 the message is discarded. Valid messages received by in.rwhod are
69 placed in files named whod.hostname in the directory /var/spool/rwho.
70 These files contain only the most recent message, in the format
71 described above.
72
73
74 Status messages are generated approximately once every 3 minutes.
75
77 The following options are supported:
78
79 -m [ ttl ] Use the rwho IP multicast address (224.0.1.3) when
80 transmitting. Receive announcements both on this multi‐
81 cast address and on the IP broadcast address. If ttl is
82 not specified in.rwhod multicasts on all interfaces but
83 with the IP TimeToLive set to 1 (that is, packets are
84 not forwarded by multicast routers.) If ttl is specified
85 in.rwhod only transmits packets on one interface and set‐
86 ting the IP TimeToLive to the specified ttl.
87
88
90 /var/spool/rwho/whod.* information about other machines
91
92
94 See attributes(5) for descriptions of the following attributes:
95
96
97
98
99 ┌─────────────────────────────┬─────────────────────────────┐
100 │ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
101 ├─────────────────────────────┼─────────────────────────────┤
102 │Availability │SUNWrcmds │
103 └─────────────────────────────┴─────────────────────────────┘
104
106 ruptime(1), rwho(1), w(1), uname(2), services(4), utmpx(4),
107 attributes(5)
108
110 This service can cause network performance problems when used by sev‐
111 eral hosts on the network. It is not run at most sites by default. If
112 used, include the -m multicast option.
113
115 This service takes up progressively more network bandwidth as the num‐
116 ber of hosts on the local net increases. For large networks, the cost
117 becomes prohibitive.
118
119
120 in.rwhod should relay status information between networks. People often
121 interpret the server dying as a machine going down.
122
123
124
125SunOS 5.11 8 Dec 2001 in.rwhod(1M)