1.\" $OpenBSD: netstat.1,v 1.71 2014/05/10 23:31:40 jmc Exp $ 2.\" $NetBSD: netstat.1,v 1.11 1995/10/03 21:42:43 thorpej Exp $ 3.\" 4.\" Copyright (c) 1983, 1990, 1992, 1993 5.\" The Regents of the University of California. All rights reserved. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 3. Neither the name of the University nor the names of its contributors 16.\" may be used to endorse or promote products derived from this software 17.\" without specific prior written permission. 18.\" 19.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29.\" SUCH DAMAGE. 30.\" 31.\" from: @(#)netstat.1 8.8 (Berkeley) 4/18/94 32.\" 33.Dd $Mdocdate: May 10 2014 $ 34.Dt NETSTAT 1 35.Os 36.Sh NAME 37.Nm netstat 38.Nd show network status 39.Sh SYNOPSIS 40.Nm netstat 41.Op Fl AaBn 42.Op Fl f Ar address_family 43.Op Fl p Ar protocol 44.Op Fl M Ar core 45.Op Fl N Ar system 46.Nm netstat 47.Bk -words 48.Op Fl bdFgilmnqrstu 49.Op Fl f Ar address_family 50.Op Fl p Ar protocol 51.Op Fl M Ar core 52.Op Fl N Ar system 53.Op Fl T Ar tableid 54.Ek 55.Nm netstat 56.Op Fl bdhn 57.Op Fl c Ar count 58.Op Fl I Ar interface 59.Op Fl M Ar core 60.Op Fl N Ar system 61.Op Fl w Ar wait 62.Nm netstat 63.Op Fl v 64.Op Fl M Ar core 65.Op Fl N Ar system 66.Fl P Ar pcbaddr 67.Nm netstat 68.Op Fl s 69.Op Fl M Ar core 70.Op Fl N Ar system 71.Op Fl p Ar protocol 72.Nm netstat 73.Op Fl a 74.Op Fl f Ar address_family 75.Op Fl p Ar protocol 76.Op Fl i | I Ar interface 77.Nm netstat 78.Op Fl W Ar interface 79.Sh DESCRIPTION 80The 81.Nm 82command symbolically displays the contents of various network-related 83data structures. 84There are a number of output formats, 85depending on the options for the information presented. 86.Pp 87The first form of the command displays a list of active sockets for 88each protocol. 89The second form presents the contents of one of the other network 90data structures according to the option selected. 91Using the third form, with a 92.Ar wait 93interval specified, 94.Nm 95will continuously display the information regarding packet 96traffic on the configured network interfaces. 97The fourth form displays internals of the protocol control block (PCB) 98and the socket structure. 99The fifth form displays statistics about the named protocol. 100The sixth form displays per interface statistics for 101the specified address family. 102The final form displays per interface statistics for 103the specified wireless (802.11) device. 104.Pp 105The options are as follows: 106.Bl -tag -width Ds 107.It Fl A 108With the default display, 109show the address of any protocol control blocks associated with sockets; used 110for debugging, e.g. with the 111.Fl P 112flag. 113.It Fl a 114With the default display, 115show the state of all sockets; normally sockets used by 116server processes are not shown. 117With the interface display (options 118.Fl I 119or 120.Fl i ) , 121show multicast addresses. 122.It Fl B 123With the default display, 124show buffer sizes for TCP sockets. 125This includes the send window size, receive window size and congestion 126window size. 127.It Fl b 128With the interface display (options 129.Fl I 130or 131.Fl i ) , 132show bytes in and out, instead of packet statistics. 133.It Fl c Ar count 134Display 135.Ar count 136updates, then exit. 137This option has no effect unless 138.Fl w 139is specified as well. 140.It Fl d 141With either the interface display (options 142.Fl I 143or 144.Fl i ) 145or an interval (option 146.Fl w ) , 147show the number of dropped packets. 148.It Fl F 149When showing routes, only show routes whose gateway are in the 150same address family as the destination. 151.It Fl f Ar address_family 152Limit statistics or address control block reports to those 153of the specified 154.Ar address_family . 155.Pp 156The following address families are recognized: 157.Bl -column "Address Family" "AF_APPLETA" "Description" -offset indent 158.It Sy "Address Family" Ta Sy "Constant" Ta Sy "Description" 159.It "encap" Ta Dv "PF_KEY" Ta "IPsec" 160.It "inet" Ta Dv "AF_INET" Ta "IP Version 4" 161.It "inet6" Ta Dv "AF_INET6" Ta "IP Version 6" 162.It "local" Ta Dv "AF_LOCAL" Ta "Local to Host (i.e., pipes)" 163.It "mpls" Ta Dv "AF_MPLS" Ta "MPLS" 164.It "pflow" Ta Dv "PF_FLOW" Ta "pflow data export" 165.It "unix" Ta Dv "AF_UNIX" Ta "Local to Host (i.e., pipes)" 166.El 167.It Fl h 168Use unit suffixes to reduce the number of digits shown with the 169.Fl b 170and 171.Fl w 172options. 173.It Fl g 174Show information related to multicast (group address) routing. 175By default, show the IP multicast virtual-interface and routing tables. 176If the 177.Fl s 178option is also present, show multicast routing statistics. 179.It Fl I Ar interface 180Show information about the specified 181.Ar interface ; 182used with a 183.Ar wait 184interval as described below. 185.Pp 186If the 187.Fl a 188option is also present, multicast addresses currently in use are shown 189for the given interface and for each IP interface address. 190Multicast addresses are shown on separate lines following the interface 191address with which they are associated. 192.Pp 193If the 194.Fl f Ar address_family 195option (with the 196.Fl s 197option) is present, show per-interface 198statistics on the given interface for the specified 199.Ar address_family . 200.It Fl i 201Show the state of interfaces which have been auto-configured 202(interfaces statically configured into a system but not 203located at boot-time are not shown). 204.Pp 205If the 206.Fl a 207option is also present, multicast addresses currently in use are shown 208for each Ethernet interface and for each IP interface address. 209Multicast addresses are shown on separate lines following the interface 210address with which they are associated. 211.Pp 212If the 213.Fl f Ar address_family 214option (with the 215.Fl s 216option) is present, show per-interface statistics on all interfaces 217for the specified 218.Ar address_family . 219.It Fl l 220With the 221.Fl g 222option, display wider fields for the IPv6 multicast routing table 223.Qq Origin 224and 225.Qq Group 226columns. 227.It Fl M Ar core 228Extract values associated with the name list from the specified core 229instead of the running kernel. 230.It Fl m 231Show statistics recorded by the memory management routines 232(the network manages a private pool of memory buffers). 233.It Fl N Ar system 234Extract the name list from the specified system instead of the running kernel. 235.It Fl n 236Show network addresses as numbers (normally 237.Nm 238interprets addresses and attempts to display them 239symbolically). 240This option may be used with any of the display formats. 241.It Fl P Ar pcbaddr 242Display the contents of the socket or protocol control block (PCB) 243located at the kernel virtual address 244.Ar pcbaddr . 245PCB addresses can be obtained using the 246.Fl A 247flag. 248When used with the 249.Fl v 250option, also print socket, domain and protocol specific structures. 251.It Fl p Ar protocol 252Restrict the output to 253.Ar protocol , 254which is either a well-known name for a protocol or an alias for it. 255Some protocol names and aliases are listed in the file 256.Pa /etc/protocols . 257The program will complain if 258.Ar protocol 259is unknown. 260If the 261.Fl s 262option is specified, the per-protocol statistics are displayed. 263Otherwise the states of the matching sockets are shown. 264.It Fl q 265Only show interfaces that have seen packets (or bytes if 266.Fl b 267is specified). 268.It Fl r 269Show the routing tables. 270If the 271.Fl s 272option is also specified, show routing statistics instead. 273When used with the 274.Fl v 275option, also print routing labels. 276.It Fl s 277Show per-protocol statistics. 278If this option is repeated, counters with a value of zero are suppressed. 279.It Fl T Ar tableid 280Select an alternate routing table to query. 281The default is to use the current routing table. 282.It Fl t 283With the 284.Fl i 285option, display the current value of the watchdog timer function. 286.It Fl u 287Limit statistics or address control block reports to the 288.Dv AF_UNIX 289address family. 290.It Fl v 291Show extra (verbose) detail for the routing tables 292.Pq Fl r , 293or avoid truncation of long addresses. 294When used with the 295.Fl P 296option, also print socket, domain and protocol specific structures. 297.It Fl W Ar interface 298(IEEE 802.11 devices only) 299Show per-interface IEEE 802.11 wireless statistics. 300.It Fl w Ar wait 301Show network interface statistics at intervals of 302.Ar wait 303seconds. 304.El 305.Pp 306The default display, for active sockets, shows the local 307and remote addresses, send and receive queue sizes (in bytes), protocol, 308and the internal state of the protocol. 309.Pp 310Address formats are of the form 311.Dq host.port 312or 313.Dq network.port 314if a socket's address specifies a network but no specific host address. 315When known, the host and network addresses are displayed symbolically 316according to the databases 317.Pa /etc/hosts 318and 319.Pa /etc/networks , 320respectively. 321If a symbolic name for an address is unknown, or if the 322.Fl n 323option is specified, the address is printed numerically, according 324to the address family. 325.Pp 326For more information regarding the Internet 327.Dq dot format , 328refer to 329.Xr inet_ntop 3 . 330Unspecified or 331.Dq wildcard 332addresses and ports appear as a single 333.Sq * . 334If a local port number is registered as being in use for RPC by 335.Xr portmap 8 , 336its RPC service name or RPC service number will be printed in 337.Dq [] 338immediately after the port number. 339.Pp 340The interface display provides a table of cumulative 341statistics regarding packets transferred, errors, and collisions. 342The network addresses of the interface 343and the maximum transmission unit (MTU) are also displayed. 344.Pp 345The routing table display indicates the available routes and their status. 346Each route consists of a destination host or network and 347a gateway to use in forwarding packets. 348If the destination is a 349network in numeric format, the netmask (in /24 style format) is appended. 350The flags field shows a collection of information about 351the route stored as binary choices. 352The individual flags are discussed in more detail in the 353.Xr route 8 354and 355.Xr route 4 356manual pages. 357.Pp 358The mapping between letters and flags is: 359.Bl -column "1" "RTF_BLACKHOLE" "Protocol specific routing flag #1." 360.It 1 Ta RTF_PROTO1 Ta "Protocol specific routing flag #1." 361.It 2 Ta RTF_PROTO2 Ta "Protocol specific routing flag #2." 362.It 3 Ta RTF_PROTO3 Ta "Protocol specific routing flag #3." 363.It B Ta RTF_BLACKHOLE Ta "Just discard pkts (during updates)." 364.It b Ta RTF_BROADCAST Ta "Correspond to a local broadcast address." 365.It C Ta RTF_CLONING Ta "Generate new routes on use." 366.It c Ta RTF_CLONED Ta "Cloned routes (generated from RTF_CLONING)." 367.It D Ta RTF_DYNAMIC Ta "Created dynamically (by redirect)." 368.It G Ta RTF_GATEWAY Ta "Destination requires forwarding by intermediary." 369.It H Ta RTF_HOST Ta "Host entry (net otherwise)." 370.It L Ta RTF_LLINFO Ta "Valid protocol to link address translation." 371.It l Ta RTF_LOCAL Ta "Correspond to a local address." 372.It M Ta RTF_MODIFIED Ta "Modified dynamically (by redirect)." 373.It P Ta RTF_MPATH Ta "Multipath route." 374.It R Ta RTF_REJECT Ta "Host or net unreachable." 375.It S Ta RTF_STATIC Ta "Manually added." 376.It T Ta RTF_MPLS Ta "MPLS route." 377.It U Ta RTF_UP Ta "Route usable." 378.It X Ta RTF_XRESOLVE Ta "External daemon translates proto to link address." 379.El 380.Pp 381Direct routes are created for each interface attached to the local host; 382the gateway field for such entries shows the address of the outgoing interface. 383The refcnt field gives the current number of active uses of the route. 384Connection oriented protocols normally hold on to a single route for the 385duration of a connection while connectionless protocols obtain a route while 386sending to the same destination. 387The use field provides a count of the number of packets sent using that route. 388The MTU entry shows the MTU associated with that route. 389This MTU value is used as the basis for the TCP maximum segment size (MSS). 390The 391.Sq L 392flag appended to the MTU value indicates that the value is 393locked, and that path MTU discovery is turned off for that route. 394A 395.Sq - 396indicates that the MTU for this route has not been set, and a default 397TCP maximum segment size will be used. 398The interface entry indicates the network interface utilized for the route. 399.Pp 400When 401.Nm 402is invoked with the 403.Fl w 404option and a 405.Ar wait 406interval argument, it displays a running count of statistics related to 407network interfaces. 408An obsolescent version of this option used a numeric parameter 409with no option, and is currently supported for backward compatibility. 410This display consists of a column for the primary interface (the first 411interface found during autoconfiguration) and a column summarizing 412information for all interfaces. 413The primary interface may be replaced with another interface with the 414.Fl I 415option. 416The first line of each screen of information contains a summary since the 417system was last rebooted. 418Subsequent lines of output show values accumulated over the preceding interval. 419.Sh SEE ALSO 420.Xr fstat 1 , 421.Xr nfsstat 1 , 422.Xr ps 1 , 423.Xr systat 1 , 424.Xr tcpbench 1 , 425.Xr top 1 , 426.Xr inet_ntop 3 , 427.Xr netintro 4 , 428.Xr route 4 , 429.Xr hosts 5 , 430.Xr networks 5 , 431.Xr protocols 5 , 432.Xr services 5 , 433.Xr iostat 8 , 434.Xr portmap 8 , 435.Xr pstat 8 , 436.Xr route 8 , 437.Xr tcpdrop 8 , 438.Xr trpt 8 , 439.Xr vmstat 8 440.Sh HISTORY 441The 442.Nm 443command appeared in 444.Bx 4.2 . 445IPv6 support was added by the WIDE/KAME project. 446.Sh BUGS 447The notion of errors is ill-defined. 448