1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
|
.\" Copyright (c) 1983, 1990, 1992, 1993
.\" The Regents of the University of California. All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\" notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in the
.\" documentation and/or other materials provided with the distribution.
.\" 3. All advertising materials mentioning features or use of this software
.\" must display the following acknowledgement:
.\" This product includes software developed by the University of
.\" California, Berkeley and its contributors.
.\" 4. Neither the name of the University nor the names of its contributors
.\" may be used to endorse or promote products derived from this software
.\" without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\" @(#)netstat.1 8.8 (Berkeley) 4/18/94
.\" $FreeBSD$
.\"
.Dd April 18, 1994
.Dt NETSTAT 1
.Os BSD 4.2
.Sh NAME
.Nm netstat
.Nd show network status
.Sh SYNOPSIS
.Nm netstat
.Op Fl Aan
.Op Fl f Ar address_family
.Op Fl M Ar core
.Op Fl N Ar system
.Nm netstat
.Op Fl bdghimnrs
.Op Fl f Ar address_family
.Op Fl M Ar core
.Op Fl N Ar system
.Nm netstat
.Op Fl bdn
.Op Fl I Ar interface
.Op Fl M Ar core
.Op Fl N Ar system
.Op Fl w Ar wait
.Nm netstat
.Op Fl p Ar protocol
.Op Fl M Ar core
.Op Fl N Ar system
.Sh DESCRIPTION
The
.Nm netstat
command symbolically displays the contents of various network-related
data structures.
There are a number of output formats,
depending on the options for the information presented.
The first form of the command displays a list of active sockets for
each protocol.
The second form presents the contents of one of the other network
data structures according to the option selected.
Using the third form, with a
.Ar wait
interval specified,
.Nm netstat
will continuously display the information regarding packet
traffic on the configured network interfaces.
The fourth form displays statistics about the named protocol.
.Pp
The options have the following meaning:
.Bl -tag -width flag
.It Fl A
With the default display,
show the address of any protocol control blocks associated with sockets; used
for debugging.
.It Fl a
With the default display,
show the state of all sockets; normally sockets used by
server processes are not shown.
With the routing table display (option
.Fl r
, as described below), show protocol-cloned routes (routes
generated by a RTF_PRCLONING parent route); normally these routes are
not shown.
.It Fl b
With the interface display (option
.Fl i
, as described below),
show the number of bytes in and out.
.It Fl d
With either interface display (option
.Fl i
or an interval, as described below),
show the number of dropped packets.
.It Fl f Ar address_family
Limit statistics or address control block reports to those
of the specified
.Ar address family .
The following address families
are recognized:
.Ar inet ,
for
.Dv AF_INET ,
.Ar ipx ,
for
.Dv AF_IPX ,
.Ar atalk ,
for
.Dv AF_APPLETALK (ddp) ,
.Ar netgraph
or
.Ar ng
for
.Dv AF_NETGRAPH ,
.\".Ar ns ,
.\"for
.\".Dv AF_NS ,
.\".Ar iso ,
.\"for
.\".Dv AF_ISO ,
and
.Ar unix ,
for
.Dv AF_UNIX .
.It Fl g
Show information related to multicast (group address) routing.
By default, show the IP Multicast virtual-interface and routing tables.
If the
.Fl s
option is also present, show multicast routing statistics.
.It Fl h
Show the state of the
.Tn IMP
host table (obsolete).
.It Fl I Ar interface
Show information about the specified interface;
used with a
.Ar wait
interval as described below.
.It Fl i
Show the state of interfaces which have been auto-configured
(interfaces statically configured into a system, but not
located at boot time are not shown).
If the
.Fl a
options is also present, multicast addresses currently in use are shown
for each Ethernet interface and for each IP interface address.
Multicast addresses are shown on separate lines following the interface
address with which they are associated.
.It Fl M
Extract values associated with the name list from the specified core
instead of the default
.Pa /dev/kmem .
.It Fl m
Show statistics recorded by the memory management routines
(the network manages a private pool of memory buffers).
.It Fl N
Extract the name list from the specified system instead of the default
.Pa /kernel .
.It Fl n
Show network addresses as numbers (normally
.Nm netstat
interprets addresses and attempts to display them
symbolically).
This option may be used with any of the display formats.
.It Fl p Ar protocol
Show statistics about
.Ar protocol ,
which is either a well-known name for a protocol or an alias for it. Some
protocol names and aliases are listed in the file
.Pa /etc/protocols .
The special protocol name ``bdg''
is used to show bridging statistics.
A null response typically means that there are no interesting numbers to
report.
The program will complain if
.Ar protocol
is unknown or if there is no statistics routine for it.
.It Fl s
Show per-protocol statistics.
If this option is repeated, counters with a value of zero are suppressed.
.It Fl r
Show the routing tables.
Use with
.Fl a
to show protocol-cloned routes.
When
.Fl s
is also present, show routing statistics instead.
.It Fl w Ar wait
Show network interface statistics at intervals of
.Ar wait
seconds.
.El
.Pp
The default display, for active sockets, shows the local
and remote addresses, send and receive queue sizes (in bytes), protocol,
and the internal state of the protocol.
Address formats are of the form ``host.port'' or ``network.port''
if a socket's address specifies a network but no specific host address.
When known the host and network addresses are displayed symbolically
according to the data bases
.Pa /etc/hosts
and
.Pa /etc/networks ,
respectively. If a symbolic name for an address is unknown, or if
the
.Fl n
option is specified, the address is printed numerically, according
to the address family.
For more information regarding
the Internet ``dot format,''
refer to
.Xr inet 3 ) .
Unspecified,
or ``wildcard'', addresses and ports appear as ``*''.
.Pp
The interface display provides a table of cumulative
statistics regarding packets transferred, errors, and collisions.
The network addresses of the interface
and the maximum transmission unit (``mtu'') are also displayed.
.Pp
The routing table display indicates the available routes and
their status. Each route consists of a destination host or network
and a gateway to use in forwarding packets. The flags field shows
a collection of information about the route stored as
binary choices. The individual flags are discussed in more
detail in the
.Xr route 8
and
.Xr route 4
manual pages.
The mapping between letters and flags is:
.Bl -column XXXX RTF_BLACKHOLE
1 RTF_PROTO1 Protocol specific routing flag #1
2 RTF_PROTO2 Protocol specific routing flag #2
3 RTF_PROTO3 Protocol specific routing flag #3
B RTF_BLACKHOLE Just discard pkts (during updates)
b RTF_BROADCAST The route represents a broadcast address
C RTF_CLONING Generate new routes on use
c RTF_PRCLONING Protocol-specified generate new routes on use
D RTF_DYNAMIC Created dynamically (by redirect)
G RTF_GATEWAY Destination requires forwarding by intermediary
H RTF_HOST Host entry (net otherwise)
L RTF_LLINFO Valid protocol to link address translation
M RTF_MODIFIED Modified dynamically (by redirect)
R RTF_REJECT Host or net unreachable
S RTF_STATIC Manually added
U RTF_UP Route usable
W RTF_WASCLONED Route was generated as a result of cloning
X RTF_XRESOLVE External daemon translates proto to link address
.El
.Pp
Direct routes are created for each
interface attached to the local host;
the gateway field for such entries shows the address of the outgoing interface.
The refcnt field gives the
current number of active uses of the route. Connection oriented
protocols normally hold on to a single route for the duration of
a connection while connectionless protocols obtain a route while sending
to the same destination.
The use field provides a count of the number of packets
sent using that route. The interface entry indicates the network
interface utilized for the route.
.Pp
When
.Nm netstat
is invoked with the
.Fl w
option and a
.Ar wait
interval argument, it displays a running count of statistics related to
network interfaces.
An obsolescent version of this option used a numeric parameter
with no option, and is currently supported for backward compatibility.
By default, this display summarizes information for all interfaces.
Information for a specific interface may be displayed with the
.Fl I
option.
.Sh SEE ALSO
.Xr fstat 1 ,
.Xr nfsstat 1 ,
.Xr sockstat 1 ,
.Xr ps 1 ,
.Xr inet 4 ,
.Xr unix 4 ,
.Xr hosts 5 ,
.Xr networks 5 ,
.Xr protocols 5 ,
.Xr services 5 ,
.Xr iostat 8 ,
.Xr trpt 8 ,
.Xr vmstat 8
.Sh HISTORY
The
.Nm netstat
command appeared in
.Bx 4.2 .
.\" .Sh FILES
.\" .Bl -tag -width /dev/kmem -compact
.\" .It Pa /kernel
.\" default kernel namelist
.\" .It Pa /dev/kmem
.\" default memory file
.\" .El
.Sh BUGS
The notion of errors is ill-defined.
|