4.3BSD-Reno/share/man/cat1/netstat.0
NETSTAT(1) UNIX Reference Manual NETSTAT(1)
NNAAMMEE
nneettssttaatt - show network status
SSYYNNOOPPSSIISS
nneettssttaatt [--AAaann] [--ff _a_d_d_r_e_s_s__f_a_m_i_l_y] [_s_y_s_t_e_m] [_c_o_r_e]
nneettssttaatt [--hhiimmnnrrss] [--ff _a_d_d_r_e_s_s__f_a_m_i_l_y] [_s_y_s_t_e_m] [_c_o_r_e]
nneettssttaatt [--nn] [--II [_i_n_t_e_r_f_a_c_e]] _i_n_t_e_r_v_a_l [_s_y_s_t_e_m] [_c_o_r_e]
nneettssttaatt [--pp _p_r_o_t_o_c_o_l] [_s_y_s_t_e_m] [_c_o_r_e]
DDEESSCCRRIIPPTTIIOONN
The nneettssttaatt 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 struc-
tures according to the option selected. Using the third form, with an
_i_n_t_e_r_v_a_l specified, nneettssttaatt will continuously display the information re-
garding packet traffic on the configured network interfaces. The fourth
form displays statistics about the named protocol.
The options have the following meaning:
--AA With the default display, show the address of any protocol con-
trol blocks associated with sockets; used for debugging.
--aa With the default display, show the state of all sockets; nor-
mally sockets used by server processes are not shown.
--dd With either interface display (option --ii or an interval, as
described below), show the number of dropped packets.
--hh Show the state of the IMP host table.
--ii Show the state of interfaces which have been auto-configured
(interfaces statically configured into a system, but not locat-
ed at boot time are not shown).
--II _i_n_t_e_r_f_a_c_e
Show information only about this interface; used with an
_i_n_t_e_r_v_a_l as described below.
--mm Show statistics recorded by the memory management routines (the
network manages a private pool of memory buffers).
--nn Show network addresses as numbers (normally nneettssttaatt interprets
addresses and attempts to display them symbolically). This op-
tion may be used with any of the display formats.
--pp _p_r_o_t_o_c_o_l
Show statistics about _p_r_o_t_o_c_o_l, 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 /_e_t_c/_p_r_o_t_o_c_o_l_s. A null
response typically means that there are no interesting numbers
to report. The program will complain if _p_r_o_t_o_c_o_l is unknown or
if there is no statistics routine for it.
--ss Show per-protocol statistics.
--rr Show the routing tables. When --ss is also present, show routing
statistics instead.
--ff _a_d_d_r_e_s_s__f_a_m_i_l_y
Limit statistics or address control block reports to those of
the specified _a_d_d_r_e_s_s _f_a_m_i_l_y. The following address families
are recognized: _i_n_e_t, for AF_INET, _n_s, for AF_NS, and _u_n_i_x, for
AF_UNIX.
The arguments, _s_y_s_t_e_m and _c_o_r_e allow substitutes for the defaults
``_v_m_u_n_i_x'' and ``/_d_e_v/_k_m_e_m''.
The default display, for active sockets, shows the local and remote ad-
dresses, 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 net-
work but no specific host address. When known the host and network ad-
dresses are displayed symbolically according to the data bases /_e_t_c/_h_o_s_t_s
and /_e_t_c/_n_e_t_w_o_r_k_s, respectively. If a symbolic name for an address is
unknown, or if the --nn option is specified, the address is printed numeri-
cally, according to the address family. For more information regarding
the Internet ``dot format,'' refer to inet(3)). Unspecified, or ``wild-
card'', 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 gate-
way 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''),
whether the route was created dynamically by a redirect (``D''), and
whether the route has been modified by a redirect (``M''). 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. Con-
nection 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 indi-
cates the network interface utilized for the route.
When nneettssttaatt is invoked with an _i_n_t_e_r_v_a_l 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 inter-
faces. The primary interface may be replaced with another interface with
the --II option. The first line of each screen of information contains a
summary since the system was last rebooted. Subsequent lines of output
show values accumulated over the preceding interval.
SSEEEE AALLSSOO
iostat(1), vmstat(1), hosts(5), networks(5), protocols(5), services(5),
trpt(8)
HHIISSTTOORRYY
NNeettssttaatt appeared in 4.2 BSD.
BBUUGGSS
The notion of errors is ill-defined. Collisions mean something else for
the IMP.