1.\" $NetBSD: netstat.1,v 1.54 2009/09/13 09:17:26 wiz Exp $ 2.\" 3.\" Copyright (c) 1983, 1990, 1992, 1993 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. Neither the name of the University nor the names of its contributors 15.\" may be used to endorse or promote products derived from this software 16.\" without specific prior written permission. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28.\" SUCH DAMAGE. 29.\" 30.\" @(#)netstat.1 8.8 (Berkeley) 4/18/94 31.\" 32.Dd September 12, 2009 33.Dt NETSTAT 1 34.Os 35.Sh NAME 36.Nm netstat 37.Nd show network status 38.Sh SYNOPSIS 39.Nm 40.Op Fl Aan 41.Op Fl f Ar address_family 42.Op Fl M Ar core 43.Op Fl N Ar system 44.Nm 45.Op Fl bdgiLmnqrSsv 46.Op Fl f Ar address_family 47.Op Fl M Ar core 48.Op Fl N Ar system 49.Nm 50.Op Fl dn 51.Op Fl I Ar interface 52.Op Fl M Ar core 53.Op Fl N Ar system 54.Op Fl w Ar wait 55.Nm 56.Op Fl M Ar core 57.Op Fl N Ar system 58.Op Fl p Ar protocol 59.Nm 60.Op Fl M Ar core 61.Op Fl N Ar system 62.Op Fl p Ar protocol 63.Fl P Ar pcbaddr 64.Nm 65.Op Fl i 66.Op Fl I Ar Interface 67.Op Fl p Ar protocol 68.Nm 69.Op Fl is 70.Op Fl f Ar address_family 71.Op Fl I Ar Interface 72.Nm 73.Op Fl s 74.Op Fl I Ar Interface 75.Fl B 76.Sh DESCRIPTION 77The 78.Nm 79command symbolically displays the contents of various network-related 80data structures. 81There are a number of output formats, 82depending on the options for the information presented. 83The first form of the command displays a list of active sockets for 84each protocol. 85The second form presents the contents of one of the other network 86data structures according to the option selected. 87Using the third form, with a 88.Ar wait 89interval specified, 90.Nm 91will continuously display the information regarding packet 92traffic on the configured network interfaces. 93The fourth form displays statistics about the named protocol. 94The fifth and sixth forms display per interface statistics for 95the specified protocol or address family. 96.Pp 97The options have the following meaning: 98.Bl -tag -width flag 99.It Fl A 100With the default display, 101show the address of any protocol control blocks associated with sockets; used 102for debugging. 103.It Fl a 104With the default display, 105show the state of all sockets; normally sockets used by 106server processes are not shown. 107.It Fl B 108With the default display, 109show the current 110.Xr bpf 4 111peers. 112To show only the peers listening to a specific interface, 113use the 114.Fl I 115option. 116If the 117.Fl s 118option is present, show the current 119.Xr bpf 4 120statistics. 121.It Fl b 122With the interface display (option 123.Fl i ) , 124show bytes in and out, instead of packets in and out. 125.It Fl d 126With either interface display (option 127.Fl i 128or an interval, as described below), 129show the number of dropped packets. 130.It Fl f Ar address_family 131Limit statistics or address control block reports to those 132of the specified 133.Ar address_family . 134The following address families 135are recognized: 136.Ar inet , 137for 138.Dv AF_INET ; 139.Ar inet6 , 140for 141.Dv AF_INET6 ; 142.Ar arp , 143for 144.Dv AF_ARP ; 145.Ar ns , 146for 147.Dv AF_NS ; 148.Ar iso , 149for 150.Dv AF_ISO ; 151.Ar atalk , 152for 153.Dv AF_APPLETALK ; 154and 155.Ar local 156or 157.Ar unix , 158for 159.Dv AF_LOCAL . 160.It Fl g 161Show information related to multicast (group address) routing. 162By default, show the IP Multicast virtual-interface and routing tables. 163If the 164.Fl s 165option is also present, show multicast routing statistics. 166.It Fl I Ar interface 167Show information about the specified interface; 168used with a 169.Ar wait 170interval as described below. 171If the 172.Fl f Ar address_family 173option (with the 174.Fl s 175option) or the 176.Fl p Ar protocol 177option is present, show per-interface statistics on the 178.Ar interface 179for the specified 180.Ar address_family 181or 182.Ar protocol , 183respectively. 184.It Fl i 185Show the state of interfaces which have been auto-configured 186(interfaces statically configured into a system, but not 187located at boot time are not shown). 188If the 189.Fl a 190options is also present, multicast addresses currently in use are shown 191for each Ethernet interface and for each IP interface address. 192Multicast addresses are shown on separate lines following the interface 193address with which they are associated. 194If the 195.Fl f Ar address_family 196option (with the 197.Fl s 198option) or the 199.Fl p Ar protocol 200option is present, show per-interface statistics on all interfaces 201for the specified 202.Ar address_family 203or 204.Ar protocol , 205respectively. 206.It Fl L 207Don't show link-level routes (e.g., IPv4 ARP or IPv6 neighbour cache). 208.It Fl M 209Extract values associated with the name list from the specified core 210instead of the default 211.Pa /dev/kmem . 212.It Fl m 213Show statistics recorded by the memory management routines 214(the network manages a private pool of memory buffers). 215.It Fl N 216Extract the name list from the specified system instead of the default 217.Pa /netbsd . 218.It Fl n 219Show network addresses and ports as numbers (normally 220.Nm 221interprets addresses and ports and attempts to display them 222symbolically). 223This option may be used with any of the display formats. 224.It Fl P Ar pcbaddr 225Dump the contents of the protocol control block (PCB) located at kernel 226virtual address 227.Ar pcbaddr . 228This address may be obtained using the 229.Fl A 230flag. 231The default protocol is TCP, but may be overridden using the 232.Fl p 233flag. 234.It Fl p Ar protocol 235Show statistics about 236.Ar protocol , 237which is either a well-known name for a protocol or an alias for it. 238Some protocol names and aliases are listed in the file 239.Pa /etc/protocols . 240A null response typically means that there are no interesting numbers to 241report. 242The program will complain if 243.Ar protocol 244is unknown or if there is no statistics routine for it. 245.It Fl q 246Show software interrupt queue setting/statistics for all protocols. 247.It Fl r 248Show the routing tables. 249When 250.Fl s 251is also present, show routing statistics instead. 252.It Fl S 253Show network addresses as numbers (as with 254.Fl n , 255but show ports symbolically). 256.It Fl s 257Show per-protocol statistics. 258If this option is repeated, counters with a value of zero are suppressed. 259.It Fl v 260Show extra (verbose) detail for the routing tables 261.Pq Fl r , 262or avoid truncation of long addresses. 263.It Fl w Ar wait 264Show network interface statistics at intervals of 265.Ar wait 266seconds. 267.It Fl X 268Force use of 269.Xr sysctl 3 270when retrieving information. 271Some features of 272.Nm 273may not be (fully) supported when using 274.Xr sysctl 3 . 275This flag forces the use of the latter regardless, and emits a message if a 276not yet fully supported feature is used in conjunction with it. 277This flag might be removed at any time; do not rely on its presence. 278.El 279.Pp 280The default display, for active sockets, shows the local 281and remote addresses, send and receive queue sizes (in bytes), protocol, 282and the internal state of the protocol. 283Address formats are of the form ``host.port'' or ``network.port'' 284if a socket's address specifies a network but no specific host address. 285When known the host and network addresses are displayed symbolically 286according to the data bases 287.Pa /etc/hosts 288and 289.Pa /etc/networks , 290respectively. 291If a symbolic name for an address is unknown, or if 292the 293.Fl n 294option is specified, the address is printed numerically, according 295to the address family. 296For more information regarding 297the Internet ``dot format,'' 298refer to 299.Xr inet 3 ) . 300Unspecified, 301or ``wildcard'', addresses and ports appear as ``*''. 302You can use the 303.Xr fstat 1 304command to find out which process or processes hold references to a socket. 305.Pp 306The interface display provides a table of cumulative 307statistics regarding packets transferred, errors, and collisions. 308The network addresses of the interface 309and the maximum transmission unit (``mtu'') are also displayed. 310.Pp 311The routing table display indicates the available routes and 312their status. 313Each route consists of a destination host or network 314and a gateway to use in forwarding packets. 315The flags field shows 316a collection of information about the route stored as 317binary choices. 318The individual flags are discussed in more 319detail in the 320.Xr route 8 321and 322.Xr route 4 323manual pages. 324The mapping between letters and flags is: 325.Bl -column XXXX RTF_BLACKHOLE 326.It 1 RTF_PROTO1 Protocol specific routing flag #1 327.It 2 RTF_PROTO2 Protocol specific routing flag #2 328.It B RTF_BLACKHOLE Just discard pkts (during updates) 329.It C RTF_CLONING Generate new routes on use 330.It c RTF_CLONED Cloned routes (generated from RTF_CLONING) 331.It D RTF_DYNAMIC Created dynamically (by redirect) 332.It G RTF_GATEWAY Destination requires forwarding by intermediary 333.It H RTF_HOST Host entry (net otherwise) 334.It L RTF_LLINFO Valid protocol to link address translation. 335.It M RTF_MODIFIED Modified dynamically (by redirect) 336.It R RTF_REJECT Host or net unreachable 337.It S RTF_STATIC Manually added 338.It U RTF_UP Route usable 339.It X RTF_XRESOLVE External daemon translates proto to link address 340.El 341.Pp 342Direct routes are created for each 343interface attached to the local host; 344the gateway field for such entries shows the address of the outgoing interface. 345The refcnt field gives the 346current number of active uses of the route. 347Connection oriented 348protocols normally hold on to a single route for the duration of 349a connection while connectionless protocols obtain a route while sending 350to the same destination. 351The use field provides a count of the number of packets 352sent using that route. 353The mtu entry shows the mtu associated with 354that route. 355This mtu value is used as the basis for the TCP maximum 356segment size. 357The 'L' flag appended to the mtu value indicates that 358the value is locked, and that path mtu discovery is turned off for 359that route. 360A 361.Sq - 362indicates that the mtu for this route has not been set, and a default 363TCP maximum segment size will be used. 364The interface entry indicates 365the network interface used for the route. 366.Pp 367When 368.Nm 369is invoked with the 370.Fl w 371option and a 372.Ar wait 373interval argument, it displays a running count of statistics related to 374network interfaces. 375An obsolescent version of this option used a numeric parameter 376with no option, and is currently supported for backward compatibility. 377This display consists of a column for the primary interface (the first 378interface found during autoconfiguration) and a column summarizing 379information for all interfaces. 380The primary interface may be replaced with another interface with the 381.Fl I 382option. 383The first line of each screen of information contains a summary since the 384system was last rebooted. 385Subsequent lines of output show values 386accumulated over the preceding interval. 387.Pp 388The first character of the flags column in the 389.Fl B 390option shows the status of the 391.Xr bpf 4 392descriptor which has three different values: 393Idle ('I'), Waiting ('W') and Timed Out ('T'). 394The second character indicates whether the promisc flag is set. 395The third character indicates the status of the immediate mode. 396The fourth character indicates whether the peer will have the ability 397to see the packets sent. 398And the fifth character shows the header complete flag status. 399.Sh SEE ALSO 400.Xr fstat 1 , 401.Xr nfsstat 1 , 402.Xr ps 1 , 403.Xr sockstat 1 , 404.Xr vmstat 1 , 405.Xr inet 3 , 406.Xr bpf 4 , 407.Xr hosts 5 , 408.Xr networks 5 , 409.Xr protocols 5 , 410.Xr services 5 , 411.Xr iostat 8 , 412.Xr trpt 8 413.Sh HISTORY 414The 415.Nm 416command appeared in 417.Bx 4.2 . 418IPv6 support was added by WIDE/KAME project. 419.\" .Sh FILES 420.\" .Bl -tag -width /dev/kmem -compact 421.\" .It Pa /netbsd 422.\" default kernel namelist 423.\" .It Pa /dev/kmem 424.\" default memory file 425.\" .El 426.Sh BUGS 427The notion of errors is ill-defined. 428