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NETSTAT !!!NETSTAT NAME SYNOPSIS DESCRIPTION OPTIONS OUTPUT NOTES FILES SEE ALSO BUGS AUTHORS ---- !!NAME netstat - Print network connections, routing tables, interface statistics, masquerade connections, and multicast memberships !!SYNOPSIS __netstat__ [[''address_family_options''] [[__--tcp__|__-t__] [[__--udp__|__-u__] [[__--raw__|__-w__] [[__--listening__|__-l__] [[__--all__|__-a__] [[__--numeric__|__-n__] [[__--numeric-hosts__] [[__--numeric-ports__] [[__--numeric-users__] [[__--symbolic__|__-N__] [[__--extend__|__-e__[[__--extend__|__-e]__] [[__--timers__|__-o__] [[__--program__|__-p__] [[__--verbose__|__-v__] [[__--continuous__|__-c]__ __netstat__ {__--route__|__-r__} [[''address_family_options''] [[__--extend__|__-e__[[__--extend__|__-e]__] [[__--verbose__|__-v__] [[__--numeric__|__-n__] [[__--numeric-hosts__] [[__--numeric-ports__] [[__--numeric-users__] [[__--continuous__|__-c]__ __netstat__ {__--interfaces__|__-i__} [[__--all__|__-a__] [[__--extend__|__-e__[[__--extend__|__-e]__] [[__--verbose__|__-v__] [[__--program__|__-p__] [[__--numeric__|__-n__] [[__--numeric-hosts__] [[__--numeric-ports__] [[__--numeric-users__] [[__--continuous__|__-c]__ __netstat__ {__--groups__|__-g__} [[__--numeric__|__-n__] [[__--numeric-hosts__] [[__--numeric-ports__] [[__--numeric-users__] [[__--continuous__|__-c]__ __netstat__ {__--masquerade__|__-M__} [[__--extend__|__-e__] [[__--numeric__|__-n__] [[__--numeric-hosts__] [[__--numeric-ports__] [[__--numeric-users__] [[__--continuous__|__-c]__ __netstat__ {__--statistics__|__-s__} [[__--tcp__|__-t__] [[__--udp__|__-u__] [[__--raw__|__-w__] __netstat__ {__--version__|__-V__} __netstat__ {__--help__|__-h__} ''address_family_options'': [[__--protocol=__{__inet__,__unix__,__ipx__,__ax25__,__netrom__,__ddp__}[[,__...]__] [[__--unix__|__-x__] [[__--inet__|__--ip__] [[__--ax25__] [[__--ipx__] [[__--netrom__] [[__--ddp__] !!DESCRIPTION __Netstat__ prints information about the Linux networking subsystem. The type of information printed is controlled by the first argument, as follows: __(none)__ By default, __netstat__ displays a list of open sockets. If you don't specify any address families, then the active sockets of all configured address families will be printed. __--route , -r__ Display the kernel routing tables. __--groups , -g__ Display multicast group membership information for IPv4 and IPv6. __--interface, -i__ Display a table of all network interfaces. __--masquerade , -M__ Display a list of masqueraded connections. __--statistics , -s__ Display summary statistics for each protocol. !!OPTIONS __--verbose , -v__ Tell the user what is going on by being verbose. Especially print some useful information about unconfigured address families. __--numeric , -n__ Show numerical addresses instead of trying to determine symbolic host, port or user names. __--numeric-hosts__ shows numerical host addresses but does not affect the resolution of port or user names. __--numeric-ports__ shows numerical port numbers but does not affect the resolution of host or user names. __--numeric-users__ shows numerical user IDs but does not affect the resolution of host or port names. __--protocol=__''family'' , __-A__ Specifies the address families (perhaps better described as low level protocols) for which connections are to be shown. ''family'' is a comma (',') separated list of address family keywords like __inet__, __unix__, __ipx__, __ax25__, __netrom__, and __ddp__. This has the same effect as using the __--inet__, __--unix__ (__-x__), __--ipx__, __--ax25__, __--netrom__, and __--ddp__ options. The address family __inet__ includes raw, udp and tcp protocol sockets. __-c, --continuous__ This will cause __netstat__ to print the selected information every second continuously. __-e, --extend__ Display additional information. Use this option twice for maximum detail. __-o, --timers__ Include information related to networking timers. __-p, --program__ Show the PID and name of the program to which each socket belongs. __-l, --listening__ Show only listening sockets. (These are omitted by default.) __-a, --all__ Show both listening and non-listening sockets. With the __--interfaces__ option, show interfaces that are not up __-F__ Print routing information from the FIB. (This is the default.) __-C__ Print routing information from the route cache. ''UP''. !!OUTPUT __Active Internet connections__ (TCP, UDP, raw) __Proto__ The protocol (tcp, udp, raw) used by the socket. __Recv-Q__ The count of bytes not copied by the user program connected to this socket. __Send-Q__ The count of bytes not acknowledged by the remote host. __Local Address__ Address and port number of the local end of the socket. Unless the __--numeric__ (__-n__) option is specified, the socket address is resolved to its canonical host name (FQDN), and the port number is translated into the corresponding service name. __Foreign Address__ Address and port number of the remote end of the socket. Analogous to __State__ The state of the socket. Since there are no states in raw mode and usually no states used in UDP, this column may be left blank. Normally this can be one of several values: ''ESTABLISHED'' The socket has an established connection. ''SYN_SENT'' The socket is actively attempting to establish a connection. ''SYN_RECV'' A connection request has been received from the network. ''FIN_WAIT1'' The socket is closed, and the connection is shutting down. ''FIN_WAIT2'' Connection is closed, and the socket is waiting for a shutdown from the remote end. ''TIME_WAIT'' The socket is waiting after close to handle packets still in the network. ''CLOSE'' The socket is not being used. ''CLOSE_WAIT'' The remote end has shut down, waiting for the socket to close. ''LAST_ACK'' The remote end has shut down, and the socket is closed. Waiting for acknowledgement. ''LISTEN'' The socket is listening for incoming connections. Such sockets are not included in the output unless you specify the __--listening__ (__-l__) or __--all__ (__-a__) option. ''CLOSING'' Both sockets are shut down but we still don't have all our data sent. ''UNKNOWN'' The state of the socket is unknown. __User__ The username or the user id (UID) of the owner of the socket. __PID/Program name__ Slash-separated pair of the process id (PID) and process name of the process that owns the socket. __--program__ causes this column to be included. You will also need ''superuser'' privileges to see this information on sockets you don't own. This identification information is not yet available for IPX sockets. __Timer__ (this needs to be written) __Active UNIX domain Sockets__ __Proto__ The protocol (usually unix) used by the socket. __!RefCnt__ The reference count (i.e. attached processes via this socket). __Flags__ The flags displayed is SO_ACCEPTON (displayed as __ACC__), SO_WAITDATA (__W__) or SO_NOSPACE (__N__). SO_ACCECPTON is used on unconnected sockets if their corresponding processes are waiting for a connect request. The other flags are not of normal interest. __Type__ There are several types of socket access: ''SOCK_DGRAM'' The socket is used in Datagram (connectionless) mode. ''SOCK_STREAM'' This is a stream (connection) socket. ''SOCK_RAW'' The socket is used as a raw socket. ''SOCK_RDM'' This one serves reliably-delivered messages. ''SOCK_SEQPACKET'' This is a sequential packet socket. ''SOCK_PACKET'' Raw interface access socket. ''UNKNOWN'' Who ever knows what the future will bring us - just fill in here :-) __State__ This field will contain one of the following Keywords: ''FREE'' The socket is not allocated ''LISTENING'' The socket is listening for a connection request. Such sockets are only included in the output if you specify the __--listening__ (__-l__) or __--all__ (__-a__) option. ''CONNECTING'' The socket is about to establish a connection. ''CONNECTED'' The socket is connected. ''DISCONNECTING'' The socket is disconnecting. ''(empty)'' The socket is not connected to another one. ''UNKNOWN'' This state should never happen. __PID/Program name__ Process ID (PID) and process name of the process that has the socket open. More info available in __Active Internet connections__ section written above. __Path__ This is the path name as which the corresponding processes attached to the socket. __Active IPX sockets__ (this needs to be done by somebody who knows it) __Active NET/ROM sockets__ (this needs to be done by somebody who knows it) __Active AX.25 sockets__ (this needs to be done by somebody who knows it) !!NOTES Starting with Linux release 2.2 __netstat -i__ does not show interface statistics for alias interfaces. To get per alias interface counters you need to setup explicit rules using the __ipchains(8)__ command. !!FILES ''/etc/services'' -- The services translation file ''/proc'' -- Mount point for the proc filesystem, which gives access to kernel status information via the following files. ''/proc/net/dev'' -- device information ''/proc/net/raw'' -- raw socket information ''/proc/net/tcp'' -- TCP socket information ''/proc/net/udp'' -- UDP socket information ''/proc/net/igmp'' -- IGMP multicast information ''/proc/net/unix'' -- Unix domain socket information ''/proc/net/ipx'' -- IPX socket information ''/proc/net/ax25'' -- AX25 socket information ''/proc/net/appletalk'' -- DDP (appletalk) socket information ''/proc/net/nr'' -- NET/ROM socket information ''/proc/net/route'' -- IP routing information ''/proc/net/ax25_route'' -- AX25 routing information ''/proc/net/ipx_route'' -- IPX routing information ''/proc/net/nr_nodes'' -- NET/ROM nodelist ''/proc/net/nr_neigh'' -- NET/ROM neighbours ''/proc/net/ip_masquerade'' -- masqueraded connections ''/proc/net/snmp'' -- statistics !!SEE ALSO route(8), ifconfig(8), ipchains(8), iptables(8), proc(5) !!BUGS Occasionally strange information may appear if a socket changes as it is viewed. This is unlikely to occur. !!AUTHORS The netstat user interface was written by Fred Baumgarten The man page and the command included in the net-tools package is totally rewritten by Bernd Eckenfels ----
9 pages link to
netstat(8)
:
Man8n
arp(8)
icmp(7)
ifconfig(8)
rarp(8)
route(8)
proc(5)
NetworkingUtilities
AdvancedUserTips
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