NETSTAT(1M-SysV) RISC/os Reference Manual NETSTAT(1M-SysV)
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 informa-
tion 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 con-
tinuously display the information regarding packet traffic
on the configured network interfaces.
The options have the following meaning:
-A With the default display, show the address of any pro-
tocol control blocks associated with sockets; used for
debugging.
-a With the default display, show the state of all sock-
ets; normally sockets used by server processes are not
shown.
-h Show the state of the IMP host table.
-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 rou-
tines (the network manages a private pool of memory
buffers).
-n Show network addresses as numbers (normally netstat
interprets addresses and attempts to display them sym-
bolically). This option may be used with any of the
display formats.
-s Show per-protocol statistics.
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-r Show the routing tables. When -s is also present, show
routing statistics instead.
-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 ``/unix'' 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 statis-
tics 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'') or a host (``H''),
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 connec-
tionless 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 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 pri-
mary interface (the first interface found during
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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
each screen of information contains a summary since the sys-
tem was last rebooted. Subsequent lines of output show
values accumulated over the preceding interval.
SEE ALSO
iostat(1), vmstat(1), trpt(1M) in the User's Reference
Manual.
hosts(4), networks(4), protocols(4), services(4), in the
Programmer's Reference Manual.
ERRORS
The notion of errors is ill-defined. Collisions mean some-
thing else for the IMP.
ORIGIN
4.3 BSD
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