'\"macro stdmacro
.if n .pH g1a.comsat @(#)comsat	40.5 of 10/10/89
.\" Copyright 1989 AT&T
.nr X
.if \nX=0 .ds x} comsat 1M "TCP/IP" "\&"
.if \nX=1 .ds x} comsat 1M "TCP/IP"
.if \nX=2 .ds x} comsat 1M "" "\&"
.if \nX=3 .ds x} comsat "" "" "\&"
.TH \*(x}
.SH NAME
\f4comsat\f1, \f4in.comsat\f1 \- biff server
.SH SYNOPSIS
\f4in.comsat\f1
.SH DESCRIPTION
\f4comsat\f1
is the server process which listens for reports of incoming
mail and notifies users who have requested to be told when
mail arrives.
It is invoked as needed by
\f4inetd\f1(1M),
and times out if inactive for a few minutes.
.LP
\f4comsat\f1
listens on a datagram port associated with the
\f4biff\f1
service specification [see
\f4services\f1(4)]
for one line messages of the form
.IP
\f2user\f4@\f2mailbox\f4-\f2offset\f1
.LP
If the
.I user
specified is logged in to the system and the associated terminal has
the owner execute bit turned on (by a
\f4biff y\f1),
the
.I offset
is used as a seek offset into the appropriate mailbox file and
the first 7 lines or 560 characters of the message are printed
on the user's terminal.  Lines which appear to be part of
the message header other than the
\f4From\f1,
\f4To\f1, 
\f4Date\f1,
or
\f4Subject\f1
lines are not printed when displaying the
message.
.SH FILES
.PD 0
.TP 20
\f4/var/utmp\f1
who's logged on and on what terminals
.PD
.SH "SEE ALSO"
\f4services\f1(4),
\f4inetd\f1(1M).
.SH NOTES
The message header filtering is prone to error.
