Current File : //usr/man/man1m/in.rwhod.1m

'\" te
.\"  Copyright 1989 AT&T
.\" Copyright (C) 2001, Sun Microsystems, Inc. All Rights Reserved
.TH in.rwhod 1M "8 Dec 2001" "SunOS 5.11" "System Administration Commands"
.SH NAME
in.rwhod, rwhod \- system status server
.SH SYNOPSIS
.LP
.nf
\fB/usr/sbin/in.rwhod\fR [\fB-m\fR [\fIttl\fR]]
.fi

.SH DESCRIPTION
.sp
.LP
\fBin.rwhod\fR is the server which maintains the database used by the \fBrwho\fR(1) and \fBruptime\fR(1) programs.  Its operation is predicated on the ability to broadcast or multicast messages on a network.
.sp
.LP
\fBin.rwhod\fR operates as both a producer and consumer of status information. As a producer of information it periodically queries the state of the system and constructs status messages which are broadcast or multicast on a network. As a consumer of information, it listens for other \fBin.rwhod\fR servers' status messages, validating them, then recording them in a collection of files located in the directory \fB/var/spool/rwho\fR.
.sp
.LP
The \fBrwho\fR server transmits and receives messages at the port indicated in the \fBrwho\fR service specification, see \fBservices\fR(4). The messages sent and received are defined in \fB/usr/include/protocols/rwhod.h\fR and are of the form:
.sp
.in +2
.nf
struct  outmp {      
        char     out_line[8];   /* tty name */      
        char     out_name[8];   /* user id */      
        long     out_time;      /* time on */ 
}; 
struct  whod {      
        char     wd_vers;      
        char     wd_type;      
        char     wd_fill[2];     
        int      wd_sendtime;      
        int      wd_recvtime;      
        char     wd_hostname[32];      
        int      wd_loadav[3];      
        int      wd_boottime;      
        struct   whoent {           
                 struct   outmp we_utmp;           
                 int      we_idle;      
     } wd_we[1024 / sizeof (struct whoent)];
 };
.fi
.in -2
.sp

.sp
.LP
All fields are converted to network byte order prior to transmission.  The load averages are as calculated by the \fBw\fR(1) program, and represent load averages over the 1, 5, and 15 minute intervals prior to a server's transmission.  The host name included is that returned by the \fBuname\fR(2) system call. The array at the end of the message contains information about the users who are logged in to the sending machine.  This information includes the contents of the \fButmpx\fR(4) entry for each non-idle terminal line and a value indicating the time since a character was last received on the terminal line.
.sp
.LP
Messages received by the \fBrwho\fR server are discarded unless they originated at a \fBrwho\fR server's port.  In addition, if the host's name, as specified in the message, contains any unprintable \fBASCII\fR characters, the message is discarded. Valid messages received by \fBin.rwhod\fR are placed in files named \fBwhod.\fR\fBhostname\fR in the directory \fB/var/spool/rwho\fR. These files contain only the most recent message, in the format described above.
.sp
.LP
Status messages are generated approximately once every 3 minutes.
.SH OPTIONS
.sp
.LP
The following options are supported:
.sp
.ne 2
.mk
.na
\fB\fB\fR\fB-m\fR\fB \fR[\fI ttl \fR]\fR
.ad
.RS 14n
.rt  
Use the rwho  \fBIP\fR multicast address (224.0.1.3) when transmitting. Receive announcements both on this multicast address and on the  \fBIP\fR broadcast address. If  \fIttl\fR is not specified  \fBin.rwhod\fR multicasts on all interfaces but with the  \fBIP\fR TimeToLive set to 1 (that is, packets are not forwarded by multicast routers.) If  \fIttl\fR is specified  \fBin.rwhod\fR only transmits packets on one interface and setting the  \fBIP\fR TimeToLive to the specified  \fIttl\fR.
.RE

.SH FILES
.sp
.ne 2
.mk
.na
\fB\fB/var/spool/rwho/whod.*\fR\fR
.ad
.RS 26n
.rt  
information about other machines
.RE

.SH ATTRIBUTES
.sp
.LP
See \fBattributes\fR(5) for descriptions of the following attributes:
.sp

.sp
.TS
tab() box;
cw(2.75i) |cw(2.75i) 
lw(2.75i) |lw(2.75i) 
.
ATTRIBUTE TYPEATTRIBUTE VALUE
_
Availabilityservice/network/network-servers
.TE

.SH SEE ALSO
.sp
.LP
\fBruptime\fR(1), \fBrwho\fR(1), \fBw\fR(1), \fBuname\fR(2), \fBservices\fR(4), \fButmpx\fR(4), \fBattributes\fR(5)
.SH WARNINGS
.sp
.LP
This service can cause network performance problems when used by several hosts on the network. It is not run at most sites by default. If used, include the \fB-m\fR multicast option.
.SH NOTES
.sp
.LP
This service takes up progressively more network bandwidth as the number of hosts on the local net increases.  For large networks, the cost becomes prohibitive.
.sp
.LP
\fBin.rwhod\fR should relay status information between networks. People often interpret the server dying as a machine going down.