xref: /freebsd/usr.bin/netstat/netstat.1 (revision 924226fba12cc9a228c73b956e1b7fa24c60b055)
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28.\"	@(#)netstat.1	8.8 (Berkeley) 4/18/94
29.\" $FreeBSD$
30.\"
31.Dd May 27, 2022
32.Dt NETSTAT 1
33.Os
34.Sh NAME
35.Nm netstat
36.Nd show network status and statistics
37.Sh SYNOPSIS
38.Bk -words
39.Bl -tag -width "netstat"
40.It Nm
41.Op Fl -libxo
42.Op Fl 46AaCLnPRSTWx
43.Op Fl f Ar protocol_family | Fl p Ar protocol
44.Op Fl M Ar core
45.Op Fl N Ar system
46.It Nm Fl i | I Ar interface
47.Op Fl -libxo
48.Op Fl 46abdhnW
49.Op Fl f Ar address_family
50.Op Fl M Ar core
51.Op Fl N Ar system
52.It Nm Fl w Ar wait
53.Op Fl -libxo
54.Op Fl I Ar interface
55.Op Fl 46d
56.Op Fl M Ar core
57.Op Fl N Ar system
58.Op Fl q Ar howmany
59.It Nm Fl s
60.Op Fl -libxo
61.Op Fl 46sz
62.Op Fl f Ar protocol_family | Fl p Ar protocol
63.Op Fl M Ar core
64.Op Fl N Ar system
65.It Nm Fl i | I Ar interface Fl s
66.Op Fl -libxo
67.Op Fl 46s
68.Op Fl f Ar protocol_family | Fl p Ar protocol
69.Op Fl M Ar core
70.Op Fl N Ar system
71.It Nm Fl m
72.Op Fl -libxo
73.Op Fl M Ar core
74.Op Fl N Ar system
75.It Nm Fl B
76.Op Fl -libxo
77.Op Fl z
78.Op Fl I Ar interface
79.It Nm Fl r
80.Op Fl -libxo
81.Op Fl 46nW
82.Op Fl F Ar fibnum
83.Op Fl f Ar address_family
84.It Nm Fl rs
85.Op Fl -libxo
86.Op Fl s
87.Op Fl M Ar core
88.Op Fl N Ar system
89.It Nm Fl g
90.Op Fl -libxo
91.Op Fl 46W
92.Op Fl f Ar address_family
93.It Nm Fl gs
94.Op Fl -libxo
95.Op Fl 46s
96.Op Fl f Ar address_family
97.Op Fl M Ar core
98.Op Fl N Ar system
99.It Nm Fl Q
100.Op Fl -libxo
101.El
102.Ek
103.Sh DESCRIPTION
104The
105.Nm
106command symbolically displays the contents of various network-related
107data structures.
108There are a number of output formats,
109depending on the options for the information presented.
110.Bl -tag -width indent
111.It Xo
112.Bk -words
113.Nm
114.Op Fl 46AaCLnRSTWx
115.Op Fl f Ar protocol_family | Fl p Ar protocol
116.Op Fl M Ar core
117.Op Fl N Ar system
118.Ek
119.Xc
120Display a list of active sockets
121(protocol control blocks)
122for each network protocol.
123.Pp
124The default display for active sockets shows the local
125and remote addresses, send and receive queue sizes (in bytes), protocol,
126and the internal state of the protocol.
127Address formats are of the form
128.Dq host.port
129or
130.Dq network.port
131if a socket's address specifies a network but no specific host address.
132When known, the host and network addresses are displayed symbolically
133according to the databases
134.Xr hosts 5
135and
136.Xr networks 5 ,
137respectively.
138If a symbolic name for an address is unknown, or if
139the
140.Fl n
141option is specified, the address is printed numerically, according
142to the address family.
143For more information regarding
144the Internet IPv4
145.Dq dot format ,
146refer to
147.Xr inet 3 .
148Unspecified,
149or
150.Dq wildcard ,
151addresses and ports appear as
152.Dq Li * .
153.Bl -tag -width indent
154.It Fl -libxo
155Generate output via
156.Xr libxo 3
157in a selection of different human and machine readable formats.
158See
159.Xr xo_parse_args 3
160for details on command line arguments.
161.It Fl 4
162Show IPv4 only.
163See
164.Sx GENERAL OPTIONS .
165.It Fl 6
166Show IPv6 only.
167See
168.Sx GENERAL OPTIONS .
169.It Fl A
170Show the address of a protocol control block (PCB)
171associated with a socket; used for debugging.
172.It Fl a
173Show the state of all sockets;
174normally sockets used by server processes are not shown.
175.It Fl c
176Show the used TCP stack for each session.
177.It Fl C
178Show the congestion control algorithm and diagnostic information of TCP sockets.
179.It Fl L
180Show the size of the various listen queues.
181The first count shows the number of unaccepted connections,
182the second count shows the amount of unaccepted incomplete connections,
183and the third count is the maximum number of queued connections.
184.It Fl n
185Do not resolve numeric addresses and port numbers to names.
186See
187.Sx GENERAL OPTIONS .
188.It Fl P
189Display the log ID for each socket.
190.It Fl R
191Display the flowid and flowtype for each socket.
192flowid is a 32 bit hardware specific identifier for each flow.
193flowtype defines which protocol fields are hashed to produce the id.
194A complete listing is available in
195.Pa sys/mbuf.h
196under
197.Dv M_HASHTYPE_* .
198.It Fl S
199Show network addresses as numbers (as with
200.Fl n )
201but show ports symbolically.
202.It Fl T
203Display diagnostic information from the TCP control block.
204Fields include the number of packets requiring retransmission,
205received out-of-order, and those advertising a zero-sized window.
206.It Fl W
207Avoid truncating addresses even if this causes some fields to overflow.
208.It Fl x
209Display socket buffer and TCP timer statistics for each
210internet socket.
211.Pp
212The
213.Fl x
214flag causes
215.Nm
216to output all the information recorded about data
217stored in the socket buffers.
218The fields are:
219.Bl -column ".Li R-HIWA"
220.It Li R-HIWA Ta Receive buffer high water mark, in bytes.
221.It Li S-HIWA Ta Send buffer high water mark, in bytes.
222.It Li R-LOWA Ta Receive buffer low water mark, in bytes.
223.It Li S-LOWA Ta Send buffer low water mark, in bytes.
224.It Li R-BCNT Ta Receive buffer byte count.
225.It Li S-BCNT Ta Send buffer byte count.
226.It Li R-BMAX Ta Maximum bytes that can be used in the receive buffer.
227.It Li S-BMAX Ta Maximum bytes that can be used in the send buffer.
228.It Li rexmt Ta Time, in seconds, to fire Retransmit Timer, or 0 if not armed.
229.It Li persist Ta Time, in seconds, to fire Retransmit Persistence, or 0 if not armed.
230.It Li keep Ta Time, in seconds, to fire Keep Alive, or 0 if not armed.
231.It Li 2msl Ta Time, in seconds, to fire 2*msl TIME_WAIT Timer, or 0 if not armed.
232.It Li delack Ta Time, in seconds, to fire Delayed ACK Timer, or 0 if not armed.
233.It Li rcvtime Ta Time, in seconds, since last packet received.
234.El
235.It Fl f Ar protocol_family
236Filter by
237.Ar protocol_family .
238See
239.Sx GENERAL OPTIONS .
240.It Fl p Ar protocol
241Filter by
242.Ar protocol .
243See
244.Sx GENERAL OPTIONS .
245.It Fl M
246Use an alternative core.
247See
248.Sx GENERAL OPTIONS .
249.It Fl N
250Use an alternative kernel image.
251See
252.Sx GENERAL OPTIONS .
253.El
254.It Xo
255.Bk -words
256.Nm
257.Fl i | I Ar interface
258.Op Fl 46abdhnW
259.Op Fl f Ar address_family
260.Op Fl M Ar core
261.Op Fl N Ar system
262.Ek
263.Xc
264Show the state of all network interfaces or a single
265.Ar interface
266which have been auto-configured
267(interfaces statically configured into a system, but not
268located at boot time are not shown).
269An asterisk
270.Pq Dq Li *
271after an interface name indicates that the interface is
272.Dq down .
273.Pp
274When
275.Nm
276is invoked with
277.Fl i
278.Pq all interfaces
279or
280.Fl I Ar interface ,
281it provides a table of cumulative
282statistics regarding packets transferred, errors, and collisions.
283The network addresses of the interface
284and the maximum transmission unit
285.Pq Dq mtu
286are also displayed.
287.Bl -tag -width indent
288.It Fl 4
289Show IPv4 only.
290See
291.Sx GENERAL OPTIONS .
292.It Fl 6
293Show IPv6 only.
294See
295.Sx GENERAL OPTIONS .
296.It Fl a
297Multicast addresses currently in use are shown
298for each Ethernet interface and for each IP interface address.
299Multicast addresses are shown on separate lines following the interface
300address with which they are associated.
301.It Fl b
302Show the number of bytes in and out.
303.It Fl d
304Show the number of dropped packets.
305.It Fl h
306Print all counters in human readable form.
307.It Fl n
308Do not resolve numeric addresses and port numbers to names.
309See
310.Sx GENERAL OPTIONS .
311.It Fl W
312Avoid truncating interface names even if this causes some fields to overflow.
313.Sx GENERAL OPTIONS .
314.It Fl f Ar protocol_family
315Filter by
316.Ar protocol_family .
317See
318.Sx GENERAL OPTIONS .
319.El
320.It Xo
321.Bk -words
322.Nm
323.Fl w Ar wait
324.Op Fl I Ar interface
325.Op Fl 46d
326.Op Fl M Ar core
327.Op Fl N Ar system
328.Op Fl q Ar howmany
329.Ek
330.Xc
331At intervals of
332.Ar wait
333seconds, display the information regarding packet traffic on all
334configured network interfaces or a single
335.Ar interface .
336.Pp
337When
338.Nm
339is invoked with the
340.Fl w
341option and a
342.Ar wait
343interval argument, it displays a running count of statistics related to
344network interfaces.
345An obsolescent version of this option used a numeric parameter
346with no option, and is currently supported for backward compatibility.
347By default, this display summarizes information for all interfaces.
348Information for a specific interface may be displayed with the
349.Fl I Ar interface
350option.
351.Bl -tag -width indent
352.It Fl I Ar interface
353Only show information regarding
354.Ar interface
355.It Fl 4
356Show IPv4 only.
357See
358.Sx GENERAL OPTIONS .
359.It Fl 6
360Show IPv6 only.
361See
362.Sx GENERAL OPTIONS .
363.It Fl d
364Show the number of dropped packets.
365.It Fl M
366Use an alternative core.
367See
368.Sx GENERAL OPTIONS .
369.It Fl N
370Use an alternative kernel image.
371See
372.Sx GENERAL OPTIONS .
373.It Fl q
374Exit after
375.Ar howmany
376outputs.
377.El
378.It Xo
379.Bk -words
380.Nm
381.Fl s
382.Op Fl 46sz
383.Op Fl f Ar protocol_family | Fl p Ar protocol
384.Op Fl M Ar core
385.Op Fl N Ar system
386.Ek
387.Xc
388Display system-wide statistics for each network protocol.
389.Bl -tag -width indent
390.It Fl 4
391Show IPv4 only.
392See
393.Sx GENERAL OPTIONS .
394.It Fl 6
395Show IPv6 only.
396See
397.Sx GENERAL OPTIONS .
398.It Fl s
399If
400.Fl s
401is repeated, counters with a value of zero are suppressed.
402.It Fl z
403Reset statistic counters after displaying them.
404.It Fl f Ar protocol_family
405Filter by
406.Ar protocol_family .
407See
408.Sx GENERAL OPTIONS .
409.It Fl p Ar protocol
410Filter by
411.Ar protocol .
412See
413.Sx GENERAL OPTIONS .
414.It Fl M
415Use an alternative core.
416See
417.Sx GENERAL OPTIONS .
418.It Fl N
419Use an alternative kernel image
420See
421.Sx GENERAL OPTIONS .
422.El
423.It Xo
424.Bk -words
425.Nm
426.Fl i | I Ar interface Fl s
427.Op Fl 46s
428.Op Fl f Ar protocol_family | Fl p Ar protocol
429.Op Fl M Ar core
430.Op Fl N Ar system
431.Ek
432.Xc
433Display per-interface statistics for each network protocol.
434.Bl -tag -width indent
435.It Fl 4
436Show IPv4 only
437See
438.Sx GENERAL OPTIONS .
439.It Fl 6
440Show IPv6 only
441See
442.Sx GENERAL OPTIONS .
443.It Fl s
444If
445.Fl s
446is repeated, counters with a value of zero are suppressed.
447.It Fl f Ar protocol_family
448Filter by
449.Ar protocol_family .
450See
451.Sx GENERAL OPTIONS .
452.It Fl p Ar protocol
453Filter by
454.Ar protocol .
455See
456.Sx GENERAL OPTIONS .
457.It Fl M
458Use an alternative core
459See
460.Sx GENERAL OPTIONS .
461.It Fl N
462Use an alternative kernel image
463See
464.Sx GENERAL OPTIONS .
465.El
466.It Xo
467.Bk -words
468.Nm
469.Fl m
470.Op Fl M Ar core
471.Op Fl N Ar system
472.Ek
473.Xc
474Show statistics recorded by the memory management routines
475.Pq Xr mbuf 9 .
476The network manages a private pool of memory buffers.
477.Bl -tag -width indent
478.It Fl M
479Use an alternative core
480See
481.Sx GENERAL OPTIONS .
482.It Fl N
483Use an alternative kernel image
484See
485.Sx GENERAL OPTIONS .
486.El
487.It Xo
488.Bk -words
489.Nm
490.Fl B
491.Op Fl z
492.Op Fl I Ar interface
493.Ek
494.Xc
495Show statistics about
496.Xr bpf 4
497peers.
498This includes information like
499how many packets have been matched, dropped and received by the
500bpf device, also information about current buffer sizes and device
501states.
502.Pp
503The
504.Xr bpf 4
505flags displayed when
506.Nm
507is invoked with the
508.Fl B
509option represent the underlying parameters of the bpf peer.
510Each flag is
511represented as a single lower case letter.
512The mapping between the letters and flags in order of appearance are:
513.Bl -column ".Li i"
514.It Li p Ta Set if listening promiscuously
515.It Li i Ta Dv BIOCIMMEDIATE No has been set on the device
516.It Li f Ta Dv BIOCGHDRCMPLT No status: source link addresses are being
517filled automatically
518.It Li s Ta Dv BIOCGSEESENT No status: see packets originating locally and
519remotely on the interface.
520.It Li a Ta Packet reception generates a signal
521.It Li l Ta Dv BIOCLOCK No status: descriptor has been locked
522.El
523.Pp
524For more information about these flags, please refer to
525.Xr bpf 4 .
526.Bl -tag -width indent
527.It Fl z
528Reset statistic counters after displaying them.
529.El
530.It Xo
531.Bk -words
532.Nm
533.Fl r
534.Op Fl 46AnW
535.Op Fl F Ar fibnum
536.Op Fl f Ar address_family
537.Op Fl M Ar core
538.Op Fl N Ar system
539.Ek
540.Xc
541Display the contents of routing tables.
542.Pp
543When
544.Nm
545is invoked with the routing table option
546.Fl r ,
547it lists the available routes and their status.
548Each route consists of a destination host or network, and a gateway to use
549in forwarding packets.
550The flags field shows a collection of information about the route stored
551as binary choices.
552The individual flags are discussed in more detail in the
553.Xr route 8
554and
555.Xr route 4
556manual pages.
557The mapping between letters and flags is:
558.Bl -column ".Li W" ".Dv RTF_WASCLONED"
559.It Li 1 Ta Dv RTF_PROTO1 Ta "Protocol specific routing flag #1"
560.It Li 2 Ta Dv RTF_PROTO2 Ta "Protocol specific routing flag #2"
561.It Li 3 Ta Dv RTF_PROTO3 Ta "Protocol specific routing flag #3"
562.It Li B Ta Dv RTF_BLACKHOLE Ta "Just discard pkts (during updates)"
563.It Li b Ta Dv RTF_BROADCAST Ta "The route represents a broadcast address"
564.It Li D Ta Dv RTF_DYNAMIC Ta "Created dynamically (by redirect)"
565.It Li G Ta Dv RTF_GATEWAY Ta "Destination requires forwarding by intermediary"
566.It Li H Ta Dv RTF_HOST Ta "Host entry (net otherwise)"
567.It Li L Ta Dv RTF_LLINFO Ta "Valid protocol to link address translation"
568.It Li M Ta Dv RTF_MODIFIED Ta "Modified dynamically (by redirect)"
569.It Li R Ta Dv RTF_REJECT Ta "Host or net unreachable"
570.It Li S Ta Dv RTF_STATIC Ta "Manually added"
571.It Li U Ta Dv RTF_UP Ta "Route usable"
572.It Li X Ta Dv RTF_XRESOLVE Ta "External daemon translates proto to link address"
573.El
574.Pp
575Direct routes are created for each
576interface attached to the local host;
577the gateway field for such entries shows the address of the outgoing interface.
578The refcnt field gives the
579current number of active uses of the route.
580Connection oriented
581protocols normally hold on to a single route for the duration of
582a connection while connectionless protocols obtain a route while sending
583to the same destination.
584The use field provides a count of the number of packets
585sent using that route.
586The interface entry indicates the network interface utilized for the route.
587.Bl -tag -width indent
588.It Fl 4
589Show IPv4 only.
590See
591.Sx GENERAL OPTIONS .
592.It Fl 6
593Show IPv6 only.
594See
595.Sx GENERAL OPTIONS .
596.It Fl n
597Do not resolve numeric addresses and port numbers to names.
598See
599.Sx GENERAL OPTIONS .
600.It Fl W
601Show the path MTU for each route, and print interface names with a
602wider field size.
603.It Fl F
604Display the routing table with the number
605.Ar fibnum .
606If the specified
607.Ar fibnum
608is -1 or
609.Fl F
610is not specified,
611the default routing table is displayed.
612.It Fl f
613Display the routing table for a particular
614.Ar address_family .
615.It Fl M
616Use an alternative core
617See
618.Sx GENERAL OPTIONS .
619.It Fl N
620Use an alternative kernel image
621See
622.Sx GENERAL OPTIONS .
623.El
624.It Xo
625.Bk -words
626.Nm
627.Fl rs
628.Op Fl s
629.Op Fl M Ar core
630.Op Fl N Ar system
631.Ek
632.Xc
633Display routing statistics.
634.Bl -tag -width indent
635.It Fl s
636If
637.Fl s
638is repeated, counters with a value of zero are suppressed.
639.It Fl M
640Use an alternative core
641See
642.Sx GENERAL OPTIONS .
643.It Fl N
644Use an alternative kernel image
645See
646.Sx GENERAL OPTIONS .
647.El
648.It Xo
649.Bk -words
650.Nm
651.Fl g
652.Op Fl 46W
653.Op Fl f Ar address_family
654.Op Fl M Ar core
655.Op Fl N Ar system
656.Ek
657.Xc
658Display the contents of the multicast virtual interface tables,
659and multicast forwarding caches.
660Entries in these tables will appear only when the kernel is
661actively forwarding multicast sessions.
662This option is applicable only to the
663.Cm inet
664and
665.Cm inet6
666address families.
667.Bl -tag -width indent
668.It Fl 4
669Show IPv4 only
670See
671.Sx GENERAL OPTIONS .
672.It Fl 6
673Show IPv6 only
674See
675.Sx GENERAL OPTIONS .
676.It Fl W
677Avoid truncating addresses even if this causes some fields to overflow.
678.It Fl f Ar protocol_family
679Filter by
680.Ar protocol_family .
681See
682.Sx GENERAL OPTIONS .
683.It Fl M
684Use an alternative core
685See
686.Sx GENERAL OPTIONS .
687.It Fl N
688Use an alternative kernel image
689See
690.Sx GENERAL OPTIONS .
691.El
692.It Xo
693.Bk -words
694.Nm
695.Fl gs
696.Op Fl 46s
697.Op Fl f Ar address_family
698.Op Fl M Ar core
699.Op Fl N Ar system
700.Ek
701.Xc
702Show multicast routing statistics.
703.Bl -tag -width indent
704.It Fl 4
705Show IPv4 only
706See
707.Sx GENERAL OPTIONS .
708.It Fl 6
709Show IPv6 only
710See
711.Sx GENERAL OPTIONS .
712.It Fl s
713If
714.Fl s
715is repeated, counters with a value of zero are suppressed.
716.It Fl f Ar protocol_family
717Filter by
718.Ar protocol_family .
719See
720.Sx GENERAL OPTIONS .
721.It Fl M
722Use an alternative core
723See
724.Sx GENERAL OPTIONS .
725.It Fl N
726Use an alternative kernel image
727See
728.Sx GENERAL OPTIONS .
729.El
730.It Xo
731.Bk -words
732.Nm
733.Fl Q
734.Ek
735.Xc
736Show
737.Xr netisr 9
738statistics.
739The flags field shows available ISR handlers:
740.Bl -column ".Li W" ".Dv NETISR_SNP_FLAGS_DRAINEDCPU"
741.It Li C Ta Dv NETISR_SNP_FLAGS_M2CPUID Ta "Able to map mbuf to cpu id"
742.It Li D Ta Dv NETISR_SNP_FLAGS_DRAINEDCPU  Ta "Has queue drain handler"
743.It Li F Ta Dv NETISR_SNP_FLAGS_M2FLOW Ta "Able to map mbuf to flow id"
744.El
745.El
746.Ss GENERAL OPTIONS
747Some options have the general meaning:
748.Bl -tag -width flag
749.It Fl 4
750Is shorthand for
751.Fl f
752.Ar inet
753.Pq Show only IPv4
754.It Fl 6
755Is shorthand for
756.Fl f
757.Ar inet6
758.Pq Show only IPv6
759.It Fl f Ar address_family , Fl p Ar protocol
760Limit display to those records
761of the specified
762.Ar address_family
763or a single
764.Ar protocol .
765The following address families and protocols are recognized:
766.Pp
767.Bl -tag -width ".Cm netgraph , ng Pq Dv AF_NETGRAPH" -compact
768.It Em Family
769.Em Protocols
770.It Cm inet Pq Dv AF_INET
771.Cm divert , icmp , igmp , ip , ipsec , pim, sctp , tcp , udp
772.It Cm inet6 Pq Dv AF_INET6
773.Cm icmp6 , ip6 , ipsec6 , rip6 , sctp , tcp , udp
774.It Cm pfkey Pq Dv PF_KEY
775.Cm pfkey
776.It Cm netgraph , ng Pq Dv AF_NETGRAPH
777.Cm ctrl , data
778.It Cm unix Pq Dv AF_UNIX
779.It Cm link Pq Dv AF_LINK
780.El
781.Pp
782The program will complain if
783.Ar protocol
784is unknown or if there is no statistics routine for it.
785.It Fl M
786Extract values associated with the name list from the specified core
787instead of the default
788.Pa /dev/kmem .
789.It Fl N
790Extract the name list from the specified system instead of the default,
791which is the kernel image the system has booted from.
792.It Fl n
793Show network addresses and ports as numbers.
794Normally
795.Nm
796attempts to resolve addresses and ports,
797and display them symbolically.
798.El
799.Sh EXAMPLES
800Show packet traffic information (packets, bytes, errors, packet drops, etc) for
801interface re0 updated every 2 seconds and exit after 5 outputs:
802.Bd -literal -offset indent
803$ netstat -w 2 -q 5 -I re0
804.Ed
805.Pp
806Show statistics for ICMP on any interface:
807.Bd -literal -offset indent
808$ netstat -s -p icmp
809.Ed
810.Pp
811Show routing tables:
812.Bd -literal -offset indent
813$ netstat -r
814.Ed
815.Pp
816Same as above, but without resolving numeric addresses and port numbers to
817names:
818.Bd -literal -offset indent
819$ netstat -rn
820.Ed
821.Sh SEE ALSO
822.Xr fstat 1 ,
823.Xr nfsstat 1 ,
824.Xr procstat 1 ,
825.Xr ps 1 ,
826.Xr sockstat 1 ,
827.Xr libxo 3 ,
828.Xr xo_parse_args 3 ,
829.Xr bpf 4 ,
830.Xr inet 4 ,
831.Xr route 4 ,
832.Xr unix 4 ,
833.Xr hosts 5 ,
834.Xr networks 5 ,
835.Xr protocols 5 ,
836.Xr services 5 ,
837.Xr iostat 8 ,
838.Xr route 8 ,
839.Xr trpt 8 ,
840.Xr vmstat 8 ,
841.Xr mbuf 9
842.Sh HISTORY
843The
844.Nm
845command appeared in
846.Bx 4.2 .
847.Pp
848IPv6 support was added by WIDE/KAME project.
849.Sh BUGS
850The notion of errors is ill-defined.
851