> Maybe we should move descriptions about link[0-2] for sl(4)
> from slattach(8) man page and remove MLINKS of slip.8 to slattach.8 ?

Here is a new diff which includes:
- move description about link[0-2] flags from slattach(8) to sl(4)
- move description about SLIP limitations to BUGS section
- remove MLINKS of slip.8 to slattach.8
- create MLINKS of slip.4 to sl.4
---
Izumi Tsutsui


Index: distrib/sets/lists/man/mi
===================================================================
RCS file: /cvsroot/src/distrib/sets/lists/man/mi,v
retrieving revision 1.905
diff -u -r1.905 mi
--- distrib/sets/lists/man/mi	27 Jun 2006 21:59:51 -0000	1.905
+++ distrib/sets/lists/man/mi	8 Jul 2006 16:29:14 -0000
@@ -1239,6 +1239,7 @@
 ./usr/share/man/cat4/sk.0			man-sys-catman		.cat
 ./usr/share/man/cat4/skc.0			man-sys-catman		.cat
 ./usr/share/man/cat4/sl.0			man-sys-catman		.cat
+./usr/share/man/cat4/slip.0			man-sys-catman		.cat
 ./usr/share/man/cat4/slhci.0			man-sys-catman		.cat
 ./usr/share/man/cat4/slide.0			man-sys-catman		.cat
 ./usr/share/man/cat4/sm.0			man-sys-catman		.cat
@@ -2244,7 +2245,7 @@
 ./usr/share/man/cat8/showq.0			man-postfix-catman	postfix,.cat
 ./usr/share/man/cat8/shutdown.0			man-sysutil-catman	.cat
 ./usr/share/man/cat8/slattach.0			man-slip-catman		.cat
-./usr/share/man/cat8/slip.0			man-slip-catman		.cat
+./usr/share/man/cat8/slip.0			man-obsolete		obsolete
 ./usr/share/man/cat8/sliplogin.0		man-slip-catman		.cat
 ./usr/share/man/cat8/slstats.0			man-slip-catman		.cat
 ./usr/share/man/cat8/smrsh.0			man-obsolete		obsolete
@@ -3594,6 +3595,7 @@
 ./usr/share/man/man4/sk.4			man-sys-man		.man
 ./usr/share/man/man4/skc.4			man-sys-man		.man
 ./usr/share/man/man4/sl.4			man-sys-man		.man
+./usr/share/man/man4/slip.4			man-sys-man		.man
 ./usr/share/man/man4/slhci.4			man-sys-man		.man
 ./usr/share/man/man4/slide.4			man-sys-man		.man
 ./usr/share/man/man4/sm.4			man-sys-man		.man
@@ -4599,7 +4601,7 @@
 ./usr/share/man/man8/showq.8			man-postfix-man		postfix,.man
 ./usr/share/man/man8/shutdown.8			man-sysutil-man		.man
 ./usr/share/man/man8/slattach.8			man-slip-man		.man
-./usr/share/man/man8/slip.8			man-slip-man		.man
+./usr/share/man/man8/slip.8			man-obsolete		obsolete
 ./usr/share/man/man8/sliplogin.8		man-slip-man		.man
 ./usr/share/man/man8/slstats.8			man-slip-man		.man
 ./usr/share/man/man8/smrsh.8			man-obsolete		obsolete
Index: sbin/slattach/Makefile
===================================================================
RCS file: /cvsroot/src/sbin/slattach/Makefile,v
retrieving revision 1.9
diff -u -r1.9 Makefile
--- sbin/slattach/Makefile	27 Jun 2005 01:00:06 -0000	1.9
+++ sbin/slattach/Makefile	8 Jul 2006 16:29:14 -0000
@@ -3,6 +3,5 @@
 
 PROG=	slattach
 MAN=	slattach.8
-MLINKS=	slattach.8 slip.8
 
 .include <bsd.prog.mk>
Index: sbin/slattach/slattach.8
===================================================================
RCS file: /cvsroot/src/sbin/slattach/slattach.8,v
retrieving revision 1.27
diff -u -r1.27 slattach.8
--- sbin/slattach/slattach.8	7 Aug 2003 10:04:40 -0000	1.27
+++ sbin/slattach/slattach.8	8 Jul 2006 16:29:14 -0000
@@ -29,12 +29,11 @@
 .\"
 .\"     @(#)slattach.8	8.2 (Berkeley) 4/1/94
 .\"
-.Dd September 3, 1999
+.Dd July 8, 2006
 .Dt SLATTACH 8
 .Os
 .Sh NAME
-.Nm slattach ,
-.Nm slip
+.Nm slattach
 .Nd attach serial lines as network interfaces
 .Sh SYNOPSIS
 .Nm
@@ -44,8 +43,26 @@
 .Ar ttyname
 .Sh DESCRIPTION
 .Nm
-is used to assign a tty line to a network interface,
-and to define the network source and destination addresses.
+is used to assign a tty line to a network interface which uses asynchronous
+serial lines.
+.Pp
+Currently the
+.Nm
+command is used to attach
+.Xr sl 4
+or
+.Xr strip 4
+interfaces.
+These interfaces have to be created using the
+.Xr ifconfig 8
+.Cm create
+subcommand before the
+.Nm
+command.
+The network source and destination addresses and other interface parameters
+are configured via
+.Xr ifconfig 8 .
+.Pp
 The following operands are supported by
 .Nm :
 .Bl -tag -width Ar
@@ -88,25 +105,6 @@
 .Ql /dev/ttyXX .
 .El
 .Pp
-In addition, the following flags to
-.Xr ifconfig 8
-control various properties of a SLIP link:
-.Bl -tag -width Ar
-.It Ar link0
-Turn on Van Jacobsen header compression.
-.It Ar -link0
-Turn off header compression.
-.It Ar link1
-Don't pass through ICMP packets.
-.It Ar -link1
-Do pass through ICMP packets.
-.It Ar link2
-If a packet with a compressed header is received, automatically enable
-compression of outgoing packets.
-.It Ar -link2
-Don't auto-enable compression.
-.El
-.Pp
 Only the super-user may attach a network interface.
 .Pp
 To detach the interface, use
@@ -123,9 +121,9 @@
 slattach \-s 4800 /dev/tty01
 .Ed
 .Sh DIAGNOSTICS
-Messages indicating that the specified interface does not exist, the
-requested address is unknown, or that the user is not privileged but
-tried to alter an interface's configuration.
+Messages indicating that the specified interface is not configured or created,
+the requested address is unknown, or that the user is not privileged
+but tried to alter an interface's configuration.
 .Sh SEE ALSO
 .Xr netstat 1 ,
 .Xr daemon 3 ,
@@ -133,9 +131,27 @@
 .Xr sl 4 ,
 .Xr strip 4 ,
 .Xr ifconfig 8 ,
-.Xr rc 8
+.Xr rc 8 ,
+.Xr sliplogin 8 ,
+.Xr slstats 8
 .Sh HISTORY
 The
 .Nm
 command appeared in
 .Bx 4.3 .
+.Sh BUGS
+There is no way to specify the interface name (sl%d etc.) to be attached by the
+.Nm
+command.
+There is no way to see which interface is assigned to the specified tty by the
+.Nm
+command, either.
+.Pp
+It would be better if the network interfaces were created by the
+.Nm
+command rather than by using the
+.Xr ifconfig 8
+.Cm create
+subcommand before the
+.Nm
+command.
Index: share/man/man4/Makefile
===================================================================
RCS file: /cvsroot/src/share/man/man4/Makefile,v
retrieving revision 1.391
diff -u -r1.391 Makefile
--- share/man/man4/Makefile	27 Jun 2006 21:43:26 -0000	1.391
+++ share/man/man4/Makefile	8 Jul 2006 16:29:14 -0000
@@ -139,6 +139,7 @@
 MLINKS+=scsi.4 scsibus.4
 MLINKS+=si.4 sw.4
 MLINKS+=sk.4 skc.4
+MLINKS+=sl.4 slip.4
 MLINKS+=speaker.4 spkr.4
 MLINKS+=tty.4 dty.4
 MLINKS+=url.4 urlphy.4
Index: share/man/man4/sl.4
===================================================================
RCS file: /cvsroot/src/share/man/man4/sl.4,v
retrieving revision 1.11
diff -u -r1.11 sl.4
--- share/man/man4/sl.4	17 Jun 2006 04:58:14 -0000	1.11
+++ share/man/man4/sl.4	8 Jul 2006 16:29:14 -0000
@@ -29,7 +29,7 @@
 .\"
 .\"     From:	@(#)lo.4	8.1 (Berkeley) 6/5/93
 .\"
-.Dd December 5, 2004
+.Dd July 8, 2006
 .Dt SL 4
 .Os
 .Sh NAME
@@ -45,6 +45,23 @@
 network interfaces using the
 .Tn SLIP
 protocol.
+.Pp
+To use the
+.Nm
+interface, the administrator must first create the interface and assign
+a tty line to it.
+The
+.Nm
+interface is created using the
+.Xr ifconfig 8
+.Cm create
+subcommand, and
+.Xr slattach 8
+is used to assign a tty line to the interface.
+Once the interface is attached, network source and destination addresses and
+other parameters are configured via
+.Xr ifconfig 8 .
+.Pp
 The
 .Nm
 interface can use Van Jacobson
@@ -52,23 +69,24 @@
 header compression and
 .Tn ICMP
 filtering.
-.Pp
-However,
-.Tn SLIP
-can only transmit
-.Tn IPv4
-packets between preconfigured hosts on an asynchronous serial link.
-It has no provision for address negotiation,
-carriage of additional protocols (e.g.
-.Tn XNS ,
-.Tn AppleTalk ,
-.Tn DECNET ) ,
-and is not designed for synchronous serial links.
-This is why
-.Tn SLIP
-has been superseded by the Point-to-Point Protocol
-.Pq Tn PPP ,
-which does all of those things, and much more.
+The following flags to
+.Xr ifconfig 8
+control these properties of a SLIP link:
+.Bl -tag -width Ar
+.It Ar link0
+Turn on Van Jacobsen header compression.
+.It Ar -link0
+Turn off header compression.
+.It Ar link1
+Don't pass through ICMP packets.
+.It Ar -link1
+Do pass through ICMP packets.
+.It Ar link2
+If a packet with a compressed header is received, automatically enable
+compression of outgoing packets.
+.It Ar -link2
+Don't auto-enable compression.
+.El 
 .Sh DIAGNOSTICS
 .Bl -diag
 .It sl%d: af%d not supported .
@@ -80,6 +98,8 @@
 .Xr inet 4 ,
 .Xr intro 4 ,
 .Xr ppp 4 ,
+.Xr strip 4 ,
+.Xr ifconfig 8 ,
 .Xr slattach 8 ,
 .Xr sliplogin 8 ,
 .Xr slstats 8
@@ -94,3 +114,19 @@
 .Nm
 device appeared in
 .Nx 1.0 .
+.Sh BUGS
+.Tn SLIP
+can only transmit
+.Tn IPv4
+packets between preconfigured hosts on an asynchronous serial link.
+It has no provision for address negotiation,
+carriage of additional protocols (e.g.
+.Tn XNS ,
+.Tn AppleTalk ,
+.Tn DECNET ) ,
+and is not designed for synchronous serial links.
+This is why
+.Tn SLIP
+has been superseded by the Point-to-Point Protocol
+.Pq Tn PPP ,
+which does all of those things, and much more.