netstat(1CC)

NAME | SYNOPSIS | DESCRIPTION | ATTRIBUTES | SEE ALSO | FILES | BUGS | RESTRICTIONS

NAME

netstat- show network status

SYNOPSIS

netstat [-Aaln] [-f address_family]
netstat [-abdghilmnrs] [-f address_family]
netstat [-bdn] [-I interface] [-w wait]
netstat [-p protocol]

DESCRIPTION

netstat is a target utility.

netstat is available in two forms:

• as a C_INIT(1M) built-in command

• as a standalone command

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 a wait interval specified, netstat will continuously display the information regarding packet traffic on the configured network interfaces. The fourth form displays statistics about the named protocol. The fifth and sixth forms display per interface statistics for the specified protocol or address family.

The options have the following meanings:

-A

Using the default display, show the address of any protocol control blocks associated with sockets; used for debugging.

-a

Using the default display, show the status of all sockets; sockets used by server processes are not usually shown. With the routing table display (option -r , as described below), show protocol-cloned routes (routes generated by a RTF_PRCLONING parent route); normally these routes are not shown.

-b

Using the interface display (option -i, as described below), show the number of bytes in and out.

-d

Using either interface display (option -i or an interval, as described below), show the number of dropped packets. On top of ChorusOS this option is also used to show the list of symbols which have been found or not found by the IOM (an ioctl is performed on /dev/kmem).

-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, inet6 for AF_INET6, ng, for AF_NETGRAPH, and unix for AF_UNIX.

-g

Show information related to multicast (group address) routing. By default, show the IP Multicast virtual-interface and routing tables. If the -s option is also present, show multicast routing statistics.

-h

Show the state of the IMP host table (obsolete).

-I interface

Show information about the specified interface; this is used with a wait interval as described below. If the -f address_family option (with the -s option) or the -p protocol option is present, show per-interface statistics on the interface for the specified address_family or protocol, respectively.

-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 -a option 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 -f address_family option (with the -s option) or the -p protocol option is present, show per-interface statistics on the interface for the specified address_family or protocol, respectively.

-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.

-l

Print full IPv6 address.

-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.

-p protocol

Show statistics about 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 /etc/protocols. A null response typically means that there are no significant numbers to report. The program will return an error message if protocol is unknown, or if there is no statistics routine for it.

-s

Show per-protocol statistics. If this option is repeated, counters with a value of zero are suppressed. When -l is also present, netstat assumes more columns are there.

-r

Show the routing tables. When -s is also present, show routing statistics instead.

-w wait

Show network interface statistics at intervals of wait seconds.

The default display, for active sockets, shows the local and remote addresses, sends and receives queue sizes (in bytes), protocols, 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(3STDC). 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 a collection of information about the route stored as binary choices. The individual flags are discussed in more detail in the route(1M) and route(7P) manual pages.

The mapping between letters and flags is:

1 RTF_PROTO2 Protocol specific routing flag #1 2 RTF_PROTO1 Protocol specific routing flag #2 3 RTF_PROTO3 Protocol specific routing flag #3 B RTF_BLACKHOLE Simply 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

Direct routes are created for each interface attached to the local host; the gateway field for these 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 used for the route.

When netstat is invoked with the -w option and a wait interval argument, it displays a running count of statistics related to network interfaces. An obsolete version of this option used a numeric parameter with no option, and is currently supported for backward compatibility. 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 using the -I option. The first line of each screen of information contains a summary of the status since the system was last rebooted. Subsequent lines of output show values accumulated over the preceding interval.

ATTRIBUTES

See attributes(5) for descriptions of the following attributes:

ATTRIBUTE TYPE	ATTRIBUTE VALUE
Interface Stability	Evolving

SEE ALSO

C_INIT(1M), nfsstat(1CC), inet(7P), hosts(4CC), networks(4CC), protocols(4CC), services(4CC)

FILES

/dev/kmem

default memory file

BUGS

The notion of errors is ill-defined.

RESTRICTIONS

On top of ChorusOS symbols are always extracted from the running system, thus not all options used to access symbols from a file are supported. Not all the symbols required by netstat are fully resolved, because ChorusOS does not support all protocol families and tables of statistics. The -d option shows the list of symbols which have been found by ChorusOS.

ChorusOS 5.0  Last Revised December 2001

NAME | SYNOPSIS | DESCRIPTION | ATTRIBUTES | SEE ALSO | FILES | BUGS | RESTRICTIONS