NAME

netstat − show network status

SYNOPSIS

netstat [-Aan] [-f address_family] [system] [core]
netstat [-R] [system] [core]
netstat [-himnrs] [-f address_family] [system] [core]
netstat [-n] [-I interface] interval [system] [core]

DESCRIPTION

netstat symbolically displays the contents of various network-related data structures.  Output format varies according to options selected.  The netstat command takes one of the three forms shown above:

• 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. 

• The third form causes netstat to display updated packet traffic data on configured network interfaces.  The display is updated at each interval.

Options are interpreted as follows:

-A Use the default display to show the address of any protocol control blocks associated with sockets.  This option is used for debugging (does not show the X.25 programmatic access control blocks.) 

-R Lists all socket names in the socket registry for NetIPC applications.  netstat -R returns only NetIPC information, not BSD IPC ("Berkeley Sockets") information. 

-a Use the default display to show the state of all sockets.  Normally sockets used by server processes are not shown.  (This option does not show the state of X.25 programmatic access sockets.) 

-h Show the state of the IMP host table. 

-i Show the state of auto-configured interfaces (interfaces statically configured into a system, but not located at boot time are not shown). 

-I interface Show information about this interface only.  This option is used with an interval as described below. 

-m Show statistics recorded by 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 can be used with any available display format. 

-s Show per-protocol statistics. 

-r Show the routing tables.  If -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, and unix for AF_UNIX. 

The arguments, system and core allow substitutes for the defaults /hp-ux 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 using gethostbyname() and getnetbyname(), respectively (see gethostbyname(3N) and getnetbyname(3N)). If a symbolic name for an address is unknown, or if the -n option is specified, the address is displayed 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 identifies which network interface was used 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.  To replace the primary interface with another interface, use the -I 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. 

DEPENDENCIES

X.25:

-A and -a options do not list X.25 programmatic access information. 

-R option is not supported over the X.25 link. 

AUTHOR

netstat was developed by the University of California, Berkeley. 

SEE ALSO

hosts(4), networks(4), gethostbyname(3N), getnetbyname(3N), protocols(4), services(4). 

Hewlett-Packard Company  —  HP-UX Release 9.0: August 1992