Linux netstat Command
The Linux netstat command is used to display network status.
Using the netstat command allows you to see the entire network status of the Linux system.
Syntax
netstat [-acCeFghilMnNoprstuvVwx][-A<network type>][--ip]
Parameter Description:
-a or --all: Display all connected sockets.
-A<network type> or --<network type>: List addresses related to the network type connection.
-c or --continuous: Continuously list network status.
-C or --cache: Display router configuration cache information.
-e or --extend: Display additional network-related information.
-F or --fib: Display routing cache.
-g or --groups: Display multicast group membership lists.
-h or --help: Online help.
-i or --interfaces: Display network interface information table.
-l or --listening: Display sockets that are listening.
-M or --masquerade: Display masqueraded network connections.
-n or --numeric: Use IP addresses directly without going through a domain name server.
-N or --netlink or --symbolic: Display symbolic link names for network hardware peripherals.
-o or --timers: Display timers.
-p or --programs: Display process ID and program name using the socket.
-r or --route: Display the routing table.
-s or --statistics: Display network work information statistics.
-t or --tcp: Display TCP transport protocol connection status.
-u or --udp: Display UDP transport protocol connection status.
-v or --verbose: Display the execution process of the command.
-V or --version: Display version information.
-w or --raw: Display RAW transport protocol connection status.
-x or --unix: This parameter has the same effect as specifying "-A unix".
--ip or --inet: This parameter has the same effect as specifying "-A inet".
Examples
Display detailed network status
# netstat -a
Display current UDP connection status
# netstat -nu
Display UDP port 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 interface 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
```
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
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-s2MLJGO5Ci