netstat(1M)
NAME
netstat − show network status
SYNOPSIS
netstat [ −anv ]
netstat [ −g | −m | −p | −s | −f address_family ] [ −n ] [ −P protocol ]
netstat {[ −i ] [ −I interface ]} [ interval ]
netstat −r [ −anv ]
netstat −M [ −ns ]
netstat −D [ −I interface ]
DESCRIPTION
netstat displays the contents of various network-related data structures in various formats, depending on the options you select.
The first form of the command displays a list of active sockets for each protocol. The second form selects one from among various other network data structures. The third form shows the state of the interfaces. The fourth form displays the routing table, the fifth form displays the multicast routing table, and the sixth form displays the state of DHCP on one or all interfaces.
OPTIONS
−a Show the state of all sockets and all routing table entries; normally, sockets used by server processes are not shown and only interface, host, network, and default routes are shown.
−f address_family Limit statistics or address control block reports to those of the specified address_family, which can be one of:
inet For the AF_INET address family
unix For the AF_UNIX address family
−g Show the multicast group memberships for all interfaces.
−i Show the state of the interfaces that are used for TCP/IP traffic. (See ifconfig(1M)).
−m Show the STREAMS statistics.
−n Show network addresses as numbers. netstat normally displays addresses as symbols. This option may be used with any of the display formats.
−p Show the address resolution (ARP) tables.
−r Show the routing tables.
−s Show per-protocol statistics. When used with the −M option, show multicast routing statistics instead.
−v Verbose. Show additional information for the sockets and the routing table.
−I interface Show the state of a particular interface. interface can be any valid interface such as ie0 or le0.
−M Show the multicast routing tables. When used with the −s option, show multicast routing statistics instead.
−P protocol Limit display of statistics or state of all sockets to those applicable to protocol.
−d Show the state of all interfaces that are under Dynamic Host Configuration Protocol (DHCP) control.
−D Show the status of DHCP configured interfaces.
OPERANDS
interval If interval is specified, netstat displays interface information over the last interval seconds, repeating forever.
DISPLAYS
Active Sockets (First Form)
The display for each active socket shows the local and remote address, the send and receive queue sizes (in bytes), the send and receive windows (in bytes), and the internal state of the protocol.
The symbolic format normally used to display socket addresses is either
hostname.port
when the name of the host is specified, or
network.port
if a socket address specifies a network but no specific host.
The numeric host address or network number associated with the socket is used to look up the corresponding symbolic hostname or network name in the hosts or networks database.
If the network or hostname for an address is not known (or if the −n option is specified), the numerical network address is shown. Unspecified, or "wildcard", addresses and ports appear as "∗". For more information regarding the Internet naming conventions, refer to inet(7P).
TCP Sockets
The possible state values for TCP sockets are as follows:
CLOSED Closed. The socket is not being used.
LISTEN Listening for incoming connections.
SYN_SENT Actively trying to establish connection.
SYN_RECEIVED Initial synchronization of the connection under way.
ESTABLISHED Connection has been established.
CLOSE_WAIT Remote shutdown; waiting for the socket to close.
FIN_WAIT_1 Socket closed; shutting down connection.
CLOSING Closed, then remote shutdown; awaiting acknowledgment.
LAST_ACK Remote shutdown, then closed; awaiting acknowledgment.
FIN_WAIT_2 Socket closed; waiting for shutdown from remote.
TIME_WAIT Wait after close for remote shutdown retransmission.
Network Data Structures (Second Form)
The form of the display depends upon which of the −g, −m, −p, or −s options you select. If you specify more than one of these options, netstat displays the information for each one of them.
Interface Status (Third Form)
The interface status display lists information for all current interfaces, one interface per line. If an interface is specified using the −I option, it displays information for only the specified interface.
The list consists of the interface name, mtu (maximum transmission unit, or maximum packet size)(see ifconfig(1M)), the network to which the interface is attached, addresses for each interface, and counter associated with the interface. The counters show the number of input packets, input errors, output packets, output errors, and collisions, respectively. For Point-to-Point interfaces, the Net/Dest field is the name or address on the other side of the link.
If the −n option is specified, the list displays the IP address instead of the interface name.
If an optional interval is specified, the output will be continuously displayed in interval seconds until interrupted by the user.
The input interface is specified using the −I option. In this case, the list only displays traffic information in columns; the specified interface is first, the total count is second. This column list has the format of:
inputle0outputinput(Total)output packets errs packets errs colls packets errs packets errs colls 227681 0 659471 1 502 261331 0 99597 1 502 10 0 0 0 0 10 0 0 0 0 8 0 0 0 0 8 0 0 0 0 10 0 2 0 0 10 0 2 0 0
If the input interface is not specified, the first interface of address family inet will be displayed.
Routing Table (Fourth Form)
The routing table display lists the available routes and the status of each. Each route consists of a destination host or network, and a gateway to use in forwarding packets. The flags column shows the status 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). If the −a option is specified, there will be routing entries with flags for combined routing and address resolution entries (A), broadcast addresses (B), and the local addresses for the host (L).
Interface 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 column gives the current number of routes that share the same link layer address.
The use column displays the number of packets sent using a combined routing and address resolution (A) or a broadcast (B) route. For a local (L) route, this count is the number of packets received, and for all other routes it is the number of times the routing entry has been used to create a new combined route and address resolution entry.
The interface entry indicates the network interface utilized for the route.
Multicast Routing Tables (Fifth Form)
The multicast routing table consists of the virtual interface table and the actual routing table.
DHCP Interface Information (Sixth Form)
The DHCP interface information consists of the interface name, its current state, lease information (when the lease began, when it will expire, and when renewal begins), and counts of the number of protocol exchanges done on behalf of the interface.
Below is a sample command line and output from a host with five interfaces under DHCP control:
# netstat −D
Interface Status Sent Received Rejects
le0 BOUND 1 1 0
(Began,Expires,Renew) = (12/04/1996 18:08, 12/04/1996 19:08,
12/04/1996 18:38) qe0 BOUND 1 1 0
(Began,Expires,Renew) = (12/04/1996 18:08, 12/04/1996 19:08,
12/04/1996 18:38) qe1 BOUND 1 1 0
(Began,Expires,Renew) = (12/04/1996 18:08, 12/04/1996 19:08,
12/04/1996 18:38) qe2 BOUND 1 1 0
(Began,Expires,Renew) = (12/04/1996 18:08, 12/04/1996 19:08,
12/04/1996 18:38) qe3 SELECTING 4 0 0
#
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
| Availability | SUNWcsu |
SEE ALSO
dhcpagent(1M), ifconfig(1M), iostat(1M), vmstat(1M), hosts(4), networks(4), protocols(4), services(4), attributes(5), inet(7P)
NOTES
The kernel’s tables can change while netstat is examining them, creating incorrect or partial displays.
SunOS 5.6 — Last change: 13 Dec 1996