NETSTAT(1N) COMMAND REFERENCE NETSTAT(1N)
NAME
netstat - show network status
SYNOPSIS
netstat [ -Aan ] [ -f address_family ] [ system ] [ core ]
netstat [ -himnrs ] [ -f address_family ] [ system ] [ core
]
netstat [ -n ] [ -I interface ] interval [ system ] [ core ]
DESCRIPTION
The 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 an interval specified, netstat
will continuously display the information regarding packet
traffic on the configured network interfaces.
OPTIONS
-A With the default display, show the address of any
protocol control blocks associated with sockets; used
for debugging.
-a With the default display, show the state of all
sockets; normally sockets used by server processes are
not shown.
-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).
-I interface
Show information only about this interface; used with
an interval as described below.
-m Show statistics recorded by the memory management
routines (the network manages a private pool of memory
buffers).
-n Show network addresses as numbers (normally netstat
interprets addresses and attempts to display them
symbolically). This option may be used with any of the
display formats.
-s Show per-protocol statistics.
-r Show the routing tables. When -s is also present, show
routing statistics instead.
Printed 4/6/89 1
NETSTAT(1N) COMMAND REFERENCE NETSTAT(1N)
-f address_family
Limit statistics or address control block reports to
those of the specified address family. The following
address families are recognized: inet, for AF_INET, ns,
for AF_NS, and unix, for AF_UNIX.
The arguments, system and core allow substitutes for the
defaults ``/vmunix'' and ``/dev/kmem''.
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
/etc/hosts and /etc/networks, respectively. If a symbolic
name for an address is unknown, or if the -n option is
specified, the address is printed numerically, according to
the address family. For more information regarding the
Internet ``dot format,'' refer to inet(3n). Unspecified, or
``wildcard'', addresses and ports appear as ``*''.
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.
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 the state of the route (``U'' if ``up''),
whether the route is to a gateway (``G''), and whether the
route was created dynamically by a redirect (``D''). 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.
When netstat is invoked with an interval argument, it
displays a running count of statistics related to network
interfaces. This display consists of a column for the
primary interface (the first interface found during
autoconfiguration) and a column summarizing information for
all interfaces. The primary interface may be replaced with
another interface with the -I option. The first line of
Printed 4/6/89 2
NETSTAT(1N) COMMAND REFERENCE NETSTAT(1N)
each screen of information contains a summary since the
system was last rebooted. Subsequent lines of output show
values accumulated over the preceding interval.
CAVEATS
The notion of errors is ill-defined.
SEE ALSO
hosts(5n), networks(5n), protocols(5n), services(5n),
Printed 4/6/89 3
%%index%%
na:336,81;
sy:417,838;
de:1255,887;
op:2142,1477;4027,3313;7748,179;
ca:7927,121;
se:8048,181;
%%index%%000000000128