221 lines
6.2 KiB
Groff
221 lines
6.2 KiB
Groff
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.\" Copyright (c) 1990, 1991 The Regents of the University of California.
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by the University of
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.\" California, Berkeley and its contributors.
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.\" 4. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)sliplogin.8 5.4 (Berkeley) 8/5/91
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.\"
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.Dd August 5, 1991
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.Dt SLIPLOGIN 8
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.Os
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.Sh NAME
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.Nm sliplogin
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.Nd attach a serial line network interface
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.Sh SYNOPSIS
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.Nm sliplogin
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.Op Ar loginname
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.Sh DESCRIPTION
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.Nm Sliplogin
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is used to turn the terminal line on standard input into
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a Serial Line IP
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.Pq Tn SLIP
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link to a remote host. To do this, the program
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searches the file
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.Pa /etc/slip.hosts
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for an entry matching
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.Ar loginname
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(which defaults to the current login name if omitted).
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If a matching entry is found, the line is configured appropriately
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for slip (8-bit transparent i/o) and converted to
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.Tn SLIP
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line
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discipline. Then a shell script is invoked to initialize the slip
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interface with the appropriate local and remote
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.Tn IP
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address,
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netmask, etc.
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.Pp
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The usual initialization script is
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.Pa /etc/slip.login
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but, if particular hosts need special initialization, the file
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.Pa /etc/slip.login. Ns Ar loginname
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will be executed instead if it exists.
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The script is invoked with the parameters
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.Bl -tag -width slipunit
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.It Em slipunit
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The unit number of the slip interface assigned to this line. E.g.,
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.Sy 0
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for
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.Sy sl0 .
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.It Em speed
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The speed of the line.
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.It Em args
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The arguments from the
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.Pa /etc/slip.hosts
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entry, in order starting with
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.Ar loginname .
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.El
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.Pp
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Only the super-user may attach a network interface. The interface is
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automatically detached when the other end hangs up or the
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.Nm sliplogin
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process dies. If the kernel slip
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module has been configured for it, all routes through that interface will
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also disappear at the same time. If there is other processing a site
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would like done on hangup, the file
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.Pa /etc/slip.logout
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or
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.Pa /etc/slip.logout. Ns Ar loginname
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is executed if it exists. It is given the same arguments as the login script.
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.Ss Format of /etc/slip.hosts
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Comments (lines starting with a `#') and blank lines are ignored.
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Other lines must start with a
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.Ar loginname
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but the remaining arguments can be whatever is appropriate for the
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.Pa slip.login
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file that will be executed for that name.
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Arguments are separated by white space and follow normal
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.Xr sh 1
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quoting conventions (however,
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.Ar loginname
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cannot be quoted).
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Usually, lines have the form
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.Bd -literal -offset indent
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loginname local-address remote-address netmask opt-args
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.Ed
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.Pp
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where
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.Em local-address
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and
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.Em remote-address
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are the IP host names or addresses of the local and remote ends of the
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slip line and
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.Em netmask
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is the appropriate IP netmask. These arguments are passed
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directly to
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.Xr ifconfig 8 .
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.Em Opt-args
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are optional arguments used to configure the line.
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.Sh EXAMPLE
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The normal use of
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.Nm sliplogin
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is to create a
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.Pa /etc/passwd
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entry for each legal, remote slip site with
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.Nm sliplogin
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as the shell for that entry. E.g.,
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.Bd -literal
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Sfoo:ikhuy6:2010:1:slip line to foo:/tmp:/etc/sliplogin
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.Ed
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.Pp
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(Our convention is to name the account used by remote host
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.Ar hostname
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as
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.Em Shostname . )
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Then an entry is added to
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.Pa slip.hosts
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that looks like:
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.Pp
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.Bd -literal -offset indent -compact
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Sfoo `hostname` foo netmask
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.Ed
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.Pp
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where
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.Em `hostname`
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will be evaluated by
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.Xr sh
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to the local host name and
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.Em netmask
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is the local host IP netmask.
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.Pp
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Note that
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.Nm sliplogin
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must be setuid to root and, while not a security hole, moral defectives
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can use it to place terminal lines in an unusable state and/or deny
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access to legitimate users of a remote slip line. To prevent this,
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a site can create a group, say
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.Em slip ,
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that only the slip login accounts are put in then make sure that
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.Pa /etc/sliplogin
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is in group
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.Em slip
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and mode 4550 (setuid root, only group
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.Em slip
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can execute binary).
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.Sh DIAGNOSTICS
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.Nm Sliplogin
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logs various information to the system log daemon,
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.Xr syslogd 8 ,
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with a facility code of
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.Em daemon .
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The messages are listed here, grouped by severity level.
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.Pp
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.Sy Error Severity
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.Bl -tag -width Ds -compact
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.It Sy ioctl (TCGETS): Em reason
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A
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.Dv TCGETS
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.Fn ioctl
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to get the line parameters failed.
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.Pp
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.It Sy ioctl (TCSETS): Em reason
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A
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.Dv TCSETS
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.Fn ioctl
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to set the line parameters failed.
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.Pp
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.It Sy /etc/slip.hosts: Em reason
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The
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.Pa /etc/slip.hosts
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file could not be opened.
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.Pp
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.It Sy access denied for Em user
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No entry for
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.Em user
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was found in
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.Pa /etc/slip.hosts .
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.El
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.Pp
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.Sy Notice Severity
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.Bl -tag -width Ds -compact
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.It Sy "attaching slip unit" Em unit Sy for Ar loginname
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.Tn SLIP
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unit
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.Em unit
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was successfully attached.
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.El
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.Sh SEE ALSO
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.Xr slattach 8 ,
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.Xr syslogd 8
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.Sh HISTORY
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The
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.Nm
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command
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.Bt
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