freebsd-dev/usr.bin/netstat/netstat.1

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.\"	@(#)netstat.1	8.8 (Berkeley) 4/18/94
.\" $FreeBSD$
.\"
.Dd June 15, 2001
.Dt NETSTAT 1
.Os
.Sh NAME
.Nm netstat
.Nd show network status
.Sh SYNOPSIS
.Nm
.Op Fl AaLlnW
.Op Fl f Ar address_family | Fl p Ar protocol
.Op Fl M Ar core
.Op Fl N Ar system
.Nm
.Op Fl gilnrsS
.Op Fl f Ar address_family
.Op Fl M Ar core
.Op Fl N Ar system
.Nm
.Fl i | I Ar interface
.Op Fl w Ar wait
.Op Fl abdgt
.Op Fl M Ar core
.Op Fl N Ar system
.Nm
.Fl s Op Fl s
.Op Fl f Ar address_family | Fl p Ar protocol
.Op Fl M Ar core
.Op Fl N Ar system
.Nm
.Fl i | I Ar interface Fl s
.Op Fl f Ar address_family | Fl p Ar protocol
.Op Fl M Ar core
.Op Fl N Ar system
.Nm
.Fl m
.Op Fl M Ar core
.Op Fl N Ar system
.Sh DESCRIPTION
The
.Nm
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
will continuously display the information regarding packet
traffic on the configured network interfaces.
The fourth form displays statistics for
the specified protocol or address familily.
The fifth form displays per-interface statistics for
the specified protocol or address family.
The sixth form displays
.Xr mbuf 9
statistics.
.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
.Dv 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 inet6  ,
for
.Dv AF_INET6  ,
.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 I Ar interface 
Show information about the specified interface;
used with a
.Ar wait
interval as described below.
If the
.Fl s
option is present, show per-interface protocol statistics on the
.Ar interface
for the specified
.Ar address_family
or
.Ar protocol ,
or for all protocol families.
.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.
If the
.Fl s
option is present, show per-interface statistics on all interfaces
for the specified
.Ar address_family
or
.Ar protocol ,
or for all protocol families.
.It Fl L
Show the size of the various listen queues.
The first count shows the
number of unaccepted connections.
The second count shows the amount of unaccepted incomplete connections.
The third count is the maximum number of queued connections.
.It Fl l
Print full IPv6 address.
.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 and ports as numbers (normally
.Nm
interprets addresses and ports 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
.Dq 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 r
Show the routing tables.
Use with
.Fl a
to show protocol-cloned routes.
When
.Fl s
is also present, show routing statistics instead.
When
.Fl l
is also present,
.Nm
assumes more columns are there and the maximum transmission unit
.Pq Dq mtu
are also displayed.
.It Fl S
Show network addresses as numbers (as with
.Fl n )
but show ports symbolically).
.It Fl s
Show per-protocol statistics.
If this option is repeated, counters with a value of zero are suppressed.
.It Fl W
In certain displays, avoid truncating addresses even if this causes
some fields to overflow.
.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
.Dq host.port
or
.Dq 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
.Dq dot format ,
refer to
.Xr inet 3 ) .
Unspecified,
or
.Dq wildcard ,
addresses and ports appear as
.Dq * .
.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
.Pq Dq 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
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
command appeared in
.Bx 4.2 .
.Pp
IPv6 support was added by WIDE/KAME project.
.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.