NETSTAT(1,C) AIX TCP/IP User's Guide NETSTAT(1,C)
-------------------------------------------------------------------------------
netstat
PURPOSE
Shows network status.
SYNTAX
+----------------+ +------------+
+-| |---| |---------------+
+------+ | +- -I interface -+ +- interval -+ |
netstat ---| |-| +------+ +------+ |-...
+- -n -+ | +-| |--| |--+ +---------------------+ |
+-| +- -A -+ +- -a -+ |--| |--+
| +----+ | +- -f address_family -+
+-| -h |--------------+
^| -i ||
|| -m ||
|| -r ||
|| -s ||
|+----+|
+------+
+----------+ +--------+
...-| |---| |---|
+- 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 information presented. With the -a option,
the command displays a list of active sockets for each protocol. With the -h,
-i, -m, -r, and -s options, the command presents the contents of one of the
other network data structures according to the option selected. If -I
interface options is used with an interval specified, netstat continuously
displays the information regarding packet traffic on the configured network
interfaces.
FLAGS
The netstat command options are:
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-A Shows the address of any protocol control blocks associated with sockets
used for debugging, with the default display.
-a Shows the state of all sockets with the default display. Normally
sockets used by server processes are not shown. Used only with the -A
option.
-h Prints the host table associated with the Arpanet IMP if one is attached
to the system and support for it has been added to the AIX kernel.
-i Shows the state of interfaces which have been auto-configured
(interfaces statically configured into a system, but not located at boot
time are not shown).
-m Shows statistics recorded by the memory management routines (the network
manages a private pool of memory buffers).
-n Shows 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.
-r Shows the routing tables. When -s is also present, shows routing
statistics instead.
-s Shows per-protocol statistics.
-t Used only with the -i flag to print interface timer information. You
can specify a watchdog function for each network interface that will run
when the watchdog timer is decremented to zero. The watchdog timer is
decremented once per second.
Only looks at UNIX-domain sockets.
-f address_family
Limits 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
UNIX for AF_UNIX
-I interface
Shows information only about this interface. Used with an interval as
described below.
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,
sends and receives queue sizes (in bytes), protocol, and the internal state of
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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 in the AIX Operating System Technical
Reference. 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
indicates the network interface utilized for the route.
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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. 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 system was last
rebooted. Subsequent lines of output show values accumulated over the
preceding interval.
EXAMPLES
$ netstat
Active Internet connections
Proto Recv-Q Send-Q Local Address Foreign Address (state)
tcp 0 0 host1.1052 host1.ftp ESTABLISHED
tcp 0 0 host1.1051 host1.telnet ESTABLISHED
tcp 0 0 host1.1050 host1.telnet ESTABLISHED
$ netstat -A
Active Internet connections
PCB Proto Recv-Q Send-Q Local Address Foreign Address (state)
f1043b0c tcp 0 0 host1.1052 host1.ftp ESTABLISHED
f1037f8c tcp 0 0 host1.1051 host1.telnet ESTABLISHED
f103818c tcp 0 0 host1.1050 host1.telnet ESTABLISHED
$ netstat -a
Active Internet connections (including servers)
Proto Recv-Q Send-Q Local Address Foreign Address (state)
tcp 0 0 host1.1052 host1.ftp ESTABLISHED
tcp 0 0 host1.1051 host1.telnet ESTABLISHED
tcp 0 0 host1.1050 host1.telnet ESTABLISHED
tcp 0 0 *.sunrpc *.* LISTEN
tcp 0 0 *.time *.* LISTEN
tcp 0 0 *.daytime *.* LISTEN
tcp 0 0 *.chargen *.* LISTEN
tcp 0 0 *.discard *.* LISTEN
tcp 0 0 *.echo *.* LISTEN
tcp 0 0 *.smtp *.* LISTEN
tcp 0 0 *.finger *.* LISTEN
tcp 0 0 *.exec *.* LISTEN
tcp 0 0 *.login *.* LISTEN
tcp 0 0 *.telnet *.* LISTEN
tcp 0 0 *.ftp *.* LISTEN
udp 0 0 *.1031 *.*
udp 0 0 *.2049 *.*
udp 0 0 *.who *.*
udp 0 0 *.sunrpc *.*
udp 0 0 *.time *.*
udp 0 0 *.daytime *.*
udp 0 0 *.chargen *.*
udp 0 0 *.discard *.*
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udp 0 0 *.echo *.*
udp 0 0 *.talk *.*
udp 0 0 *.tftp *.*
$ netstat -i
Name Mtu Network Address Ipkts Ierrs Opkts Oerrs Collis
tk0 1500 192.100.20 host1 1698272 0 507349 0 0
lo0 1536 loopback-n localhost 13098 0 13098 0 0
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$ netstat -s -r
routing:
0 bad routing redirects
0 dynamically created routes
0 new gateways due to redirects
5 destinations found unreachable
0 uses of a wildcard route
$ netstat -s
ip:
591797 total packets received
0 bad header checksums
0 with size smaller than minimum
0 with data size < data length
0 with header length < data size
0 with data length < header length
12654 fragments received
0 fragments dropped (dup or out of space)
1 fragment dropped after timeout
0 packets forwarded
68856 packets not forwardable
0 redirects sent
icmp:
10336 calls to icmp_error
0 errors not generated 'cuz old message was icmp
Output histogram:
echo reply: 9
destination unreachable: 10336
0 messages with bad code fields
0 messages < minimum length
0 bad checksums
0 messages with bad length
Input histogram:
destination unreachable: 9281
echo: 9
9 message responses generated
tcp:
0 incomplete headers
0 bad checksums
0 bad header offset fields
udp:
0 incomplete headers
0 bad data length fields
0 bad checksums
$ netstat -m
77/160 mbufs in use:
3 mbufs allocated to packet headers
26 mbufs allocated to socket structures
41 mbufs allocated to protocol control blocks
5 mbufs allocated to routing table entries
2 mbufs allocated to interface addresses
0/36 mapped pages in use
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164 Kbytes allocated to network (5% in use)
0 requests for memory denied
$ netstat -n
Active Internet connections
Proto Recv-Q Send-Q Local Address Foreign Address (state)
tcp 0 0 193.255.2.4.1052 193.255.1.4.21 ESTABLISHED
tcp 0 0 193.255.2.4.1051 193.255.1.5.23 ESTABLISHED
tcp 0 0 193.255.2.4.1050 193.255.1.7.23 ESTABLISHED
$ netstat -f inet
Active Internet connections
Proto Recv-Q Send-Q Local Address Foreign Address (state)
tcp 0 0 host1.1082 host1.telnet ESTABLISHED
tcp 0 0 host1.1052 host1.ftp ESTABLISHED
$
RELATED INFORMATION
In this book:
"hosts"
"networks"
"protocols"
"rc.tcpip, rc.tcpip.local"
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