Linux netstat command
Linux Command EncyclopediaThe Linux netstat command is used to display network status.
Using the netstat command allows you to learn about the network status of the entire Linux system.
Syntax
netstat [-acCeFghilMnNoprstuvVwx][-A<网络类型>][--ip]
Parameter Description：
- -a or --all Display all connected Sockets.
- -A<network type> or --<network type> List related addresses in connections of that network type.
- -c or --continuous Continuously list network status.
- -C or --cache Display router configuration cache information.
- -e or --extend Display other related network information.
- -F or --fib Display the routing cache.
- -g or --groups Display multicast group member lists.
- -h or --help Online help.
- -i or --interfaces Display network interface information form.
- -l or --listening Display sockets of servers being monitored.
- -M or --masquerade Display masqueraded network connections.
- -n or --numeric Use IP addresses directly without going through the domain name server.
- -N or --netlink or --symbolic Display symbolic link names of network hardware peripheral devices.
- -o or --timers Display timers.
- -p or --programs Display the program ID and program name of programs currently using the Socket.
- -r or --route Display the Routing Table.
- -s or --statistics Display network work information statistics table.
- -t or --tcp Display connection status of the TCP transport protocol.
- -u or --udp Display connection status of the UDP transport protocol.
- -v or --verbose Display command execution process.
- -V or --version Display version information.
- -w or --raw Display connection status of the RAW transport protocol.
- -x or --unix This parameter has the same effect as specifying the "-A unix" parameter.
- --ip or --inet This parameter has the same effect as specifying the "-A inet" parameter.
Examples
Display detailed network status
# netstat -a
Display current active UDP connection status
# netstat -nu
Display UDP port number usage
# netstat -apu Active Internet connections (servers and established) Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name udp 0 0 *:32768 *:* - udp 0 0 *:nfs *:* - udp 0 0 *:641 *:* 3006/rpc.statd udp 0 0 192.168.0.3:netbios-ns *:* 3537/nmbd udp 0 0 *:netbios-ns *:* 3537/nmbd udp 0 0 192.168.0.3:netbios-dgm *:* 3537/nmbd udp 0 0 *:netbios-dgm *:* 3537/nmbd udp 0 0 *:tftp *:* 3346/xinetd udp 0 0 *:999 *:* 3366/rpc.rquotad udp 0 0 *:sunrpc *:* 2986/portmap udp 0 0 *:ipp *:* 6938/cupsd udp 0 0 *:1022 *:* 3392/rpc.mountd udp 0 0 *:638 *:* 3006/rpc.statd
Display network card list
# netstat -i Kernel Interface table Iface MTU Met RX-OK RX-ERR RX-DRP RX-OVR TX-OK TX-ERR TX-DRP TX-OVR Flg eth0 1500 0 181864 0 0 0 141278 0 0 0 BMRU lo 16436 0 3362 0 0 0 3362 0 0 0 LRU
Display multicast group relationships
# netstat -g IPv6/IPv4 Group Memberships Interface RefCnt Group --------------- ------ --------------------- lo 1 ALL-SYSTEMS.MCAST.NET eth0 1 ALL-SYSTEMS.MCAST.NET lo 1 ff02::1 eth0 1 ff02::1:ff0a:b0c eth0 1 ff02::1
Display network statistics information
# netstat -s
Ip:
184695 total packets received
0 forwarded
0 incoming packets discarded
184687 incoming packets delivered
143917 requests sent out
32 outgoing packets dropped
30 dropped because of missing route
Icmp:
676 ICMP messages received
5 input ICMP message failed.
ICMP input histogram:
destination unreachable: 44
echo requests: 287
echo replies: 345
304 ICMP messages sent
0 ICMP messages failed
ICMP output histogram:
destination unreachable: 17
echo replies: 287
Tcp:
473 active connections openings
28 passive connection openings
4 failed connection attempts
11 connection resets received
1 connections established
178253 segments received
137936 segments send out
29 segments retransmited
0 bad segments received.
336 resets sent
Udp:
5714 packets received
8 packets to unknown port received.
0 packet receive errors
5419 packets sent
TcpExt:
1 resets received for embryonic SYN_RECV sockets
ArpFilter: 0
12 TCP sockets finished time wait in fast timer
572 delayed acks sent
3 delayed acks further delayed because of locked socket
13766 packets directly queued to recvmsg prequeue.
1101482 packets directly received from backlog
19599861 packets directly received from prequeue
46860 packets header predicted
14541 packets header predicted and directly queued to user
TCPPureAcks: 12259
TCPHPAcks: 9119
TCPRenoRecovery: 0
TCPSackRecovery: 0
TCPSACKReneging: 0
TCPFACKReorder: 0
TCPSACKReorder: 0
TCPRenoReorder: 0
TCPTSReorder: 0
TCPFullUndo: 0
TCPPartialUndo: 0
TCPDSACKUndo: 0
TCPLossUndo: 0
TCPLoss: 0
TCPLostRetransmit: 0
TCPRenoFailures: 0
TCPSackFailures: 0
TCPLossFailures: 0
TCPFastRetrans: 0
TCPForwardRetrans: 0
TCPSlowStartRetrans: 0
TCPTimeouts: 29
TCPRenoRecoveryFail: 0
TCPSackRecoveryFail: 0
TCPSchedulerFailed: 0
TCPRcvCollapsed: 0
TCPDSACKOldSent: 0
TCPDSACKOfoSent: 0
TCPDSACKRecv: 0
TCPDSACKOfoRecv: 0
TCPAbortOnSyn: 0
TCPAbortOnData: 1
TCPAbortOnClose: 0
TCPAbortOnMemory: 0
TCPAbortOnTimeout: 3
TCPAbortOnLinger: 0
TCPAbortFailed: 3
TCPMemoryPressures: 0
Display listening sockets
# netstat -l Active Internet connections (only servers) Proto Recv-Q Send-Q Local Address Foreign Address State tcp 0 0 *:32769 *:* LISTEN tcp 0 0 *:nfs *:* LISTEN tcp 0 0 *:644 *:* LISTEN tcp 0 0 *:1002 *:* LISTEN tcp 0 0 *:netbios-ssn *:* LISTEN tcp 0 0 *:sunrpc *:* LISTEN tcp 0 0 vm-dev:ipp *:* LISTEN tcp 0 0 *:telnet *:* LISTEN tcp 0 0 *:601 *:* LISTEN tcp 0 0 *:microsoft-ds *:* LISTEN tcp 0 0 *:http *:* LISTEN tcp 0 0 *:ssh *:* LISTEN tcp 0 0 *:https *:* LISTEN udp 0 0 *:32768 *:* udp 0 0 *:nfs *:* udp 0 0 *:641 *:* udp 0 0 192.168.0.3:netbios-ns *:* udp 0 0 *:netbios-ns *:* udp 0 0 192.168.0.3:netbios-dgm *:* udp 0 0 *:netbios-dgm *:* udp 0 0 *:tftp *:* udp 0 0 *:999 *:* udp 0 0 *:sunrpc *:* udp 0 0 *:ipp *:* udp 0 0 *:1022 *:* udp 0 0 *:638 *:* Active UNIX domain sockets (only servers) Proto RefCnt Flags Type State I-Node Path unix 2 [ ACC ] STREAM LISTENING 10621 @/tmp/fam-root- unix 2 [ ACC ] STREAM LISTENING 7096 /var/run/acpid.socket unix 2 [ ACC ] STREAM LISTENING 9792 /tmp/.gdm_socket unix 2 [ ACC ] STREAM LISTENING 9927 /tmp/.X11-unix/X0 unix 2 [ ACC ] STREAM LISTENING 10489 /tmp/ssh-lbUnUf4552/agent.4552 unix 2 [ ACC ] STREAM LISTENING 10558 /tmp/ksocket-root/kdeinit__0 unix 2 [ ACC ] STREAM LISTENING 10560 /tmp/ksocket-root/kdeinit-:0 unix 2 [ ACC ] STREAM LISTENING 10570 /tmp/.ICE-unix/dcop4664-1270815442 unix 2 [ ACC ] STREAM LISTENING 10843 /tmp/.ICE-unix/4735 unix 2 [ ACC ] STREAM LISTENING 10591 /tmp/ksocket-root/klauncherah3arc.slave-socket unix 2 [ ACC ] STREAM LISTENING 7763 /var/run/iiim/.iiimp-unix/9010 unix 2 [ ACC ] STREAM LISTENING 11047 /tmp/orbit-root/linc-1291-0-1e92c8082411 unix 2 [ ACC ] STREAM LISTENING 11053 /tmp/orbit-root/linc-128e-0-dc070659cbb3 unix 2 [ ACC ] STREAM LISTENING 8020 /var/run/dbus/system_bus_socket unix 2 [ ACC ] STREAM LISTENING 58927 /tmp/mcop-root/vm-dev-2c28-4beba75f unix 2 [ ACC ] STREAM LISTENING 7860 /tmp/.font-unix/fs7100 unix 2 [ ACC ] STREAM LISTENING 7658 /dev/gpmctl unix 2 [ ACC ] STREAM LISTENING 10498 @/tmp/dbus-s2MLJGO5CiOther Extensions