自学教程Linux netstat 命令用于显示网络状态。
利用 netstat 指令可让你得知整个 Linux 系统的网络情况。
语法
netstat [-acCeFghilMnNoprstuvVwx][-A<网络类型>][--ip]
参数说明：
- -a或--all 显示所有连线中的Socket。
- -A<网络类型>或--<网络类型> 列出该网络类型连线中的相关地址。
- -c或--continuous 持续列出网络状态。
- -C或--cache 显示路由器配置的快取信息。
- -e或--extend 显示网络其他相关信息。
- -F或--fib 显示FIB。
- -g或--groups 显示多重广播功能群组组员名单。
- -h或--help 在线帮助。
- -i或--interfaces 显示网络界面信息表单。
- -l或--listening 显示监控中的服务器的Socket。
- -M或--masquerade 显示伪装的网络连线。
- -n或--numeric 直接使用IP地址，而不通过域名服务器。
- -N或--netlink或--symbolic 显示网络硬件外围设备的符号连接名称。
- -o或--timers 显示计时器。
- -p或--programs 显示正在使用Socket的程序识别码和程序名称。
- -r或--route 显示Routing Table。
- -s或--statistics 显示网络工作信息统计表。
- -t或--tcp 显示TCP传输协议的连线状况。
- -u或--udp 显示UDP传输协议的连线状况。
- -v或--verbose 显示指令执行过程。
- -V或--version 显示版本信息。
- -w或--raw 显示RAW传输协议的连线状况。
- -x或--unix 此参数的效果和指定"-A unix"参数相同。
- --ip或--inet 此参数的效果和指定"-A inet"参数相同。
实例
显示详细的网络状况
# netstat -a
显示当前户籍UDP连接状况
# netstat -nu
显示UDP端口号的使用情况
# netstat -apu
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
udp 0 0 0.0.0.0:bootpc 0.0.0.0:* 904/dhclient
udp 0 0 VM_0_15_centos:ntp 0.0.0.0:* 633/ntpd
udp 0 0 VM_0_15_centos:ntp 0.0.0.0:* 633/ntpd
udp6 0 0 VM_0_15_centos:ntp [::]:* 633/ntpd
udp6 0 0 VM_0_15_centos:ntp [::]:* 633/ntpd显示网卡列表
# netstat -i
Kernel Interface table
Iface MTU RX-OK RX-ERR RX-DRP RX-OVR TX-OK TX-ERR TX-DRP TX-OVR Flg
eth0 1500 86045182 0 0 0 89822855 0 0 0 BMRU
lo 65536 3191314 0 0 0 3191314 0 0 0 LRU显示组播组的关系
# 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
lo 1 ff01::1
eth0 1 ff02::1:ff13:b681
eth0 1 ff02::1
eth0 1 ff01::1显示网络统计信息
# netstat -s
Ip:
87484276 total packets received
0 forwarded
0 incoming packets discarded
84675590 incoming packets delivered
91678569 requests sent out
16 dropped because of missing route
796 reassemblies required
398 packets reassembled ok
Icmp:
9595448 ICMP messages received
251 input ICMP message failed.
InCsumErrors: 1
ICMP input histogram:
destination unreachable: 2045
timeout in transit: 46
echo requests: 9593157
echo replies: 132
timestamp request: 53
timestamp reply: 9
11830537 ICMP messages sent
0 ICMP messages failed
ICMP output histogram:
destination unreachable: 2237327
echo replies: 9593157
timestamp replies: 53
IcmpMsg:
InType0: 132
InType3: 2045
InType8: 9593157
InType11: 46
InType13: 53
InType14: 9
InType165: 5
OutType0: 9593157
OutType3: 2237327
OutType14: 53
Tcp:
7017843 active connections openings
2160370 passive connection openings
31082 failed connection attempts
31692 connection resets received
47 connections established
73150557 segments received
77004081 segments send out
1298149 segments retransmited
57 bad segments received.
76811 resets sent
Udp:
1929471 packets received
89 packets to unknown port received.
0 packet receive errors
1979581 packets sent
0 receive buffer errors
0 send buffer errors
UdpLite:
TcpExt:
7258 invalid SYN cookies received
30255 resets received for embryonic SYN_RECV sockets
191 packets pruned from receive queue because of socket buffer overrun
4 ICMP packets dropped because they were out-of-window
473923 TCP sockets finished time wait in fast timer
1122 packets rejects in established connections because of timestamp
4354999 delayed acks sent
369 delayed acks further delayed because of locked socket
Quick ack mode was activated 43539 times
888 SYNs to LISTEN sockets dropped
1401958 packets directly queued to recvmsg prequeue.
725175 bytes directly in process context from backlog
60663 bytes directly received in process context from prequeue
12848035 packet headers predicted
289 packets header predicted and directly queued to user
27900018 acknowledgments not containing data payload received
6393444 predicted acknowledgments
22 times recovered from packet loss due to fast retransmit
33776 times recovered from packet loss by selective acknowledgements
7 bad SACK blocks received
Detected reordering 148 times using FACK
Detected reordering 84 times using SACK
Detected reordering 385 times using time stamp
662 congestion windows fully recovered without slow start
337 congestion windows partially recovered using Hoe heuristic
2308 congestion windows recovered without slow start by DSACK
54193 congestion windows recovered without slow start after partial ack
TCPLostRetransmit: 6904
8 timeouts after reno fast retransmit
7294 timeouts after SACK recovery
5971 timeouts in loss state
87576 fast retransmits
9224 forward retransmits
59651 retransmits in slow start
575712 other TCP timeouts
TCPLossProbes: 527038
TCPLossProbeRecovery: 320985
9 classic Reno fast retransmits failed
10573 SACK retransmits failed
1 times receiver scheduled too late for direct processing
46999 DSACKs sent for old packets
981 DSACKs sent for out of order packets
331457 DSACKs received
98 DSACKs for out of order packets received
5562 connections reset due to unexpected data
7135 connections reset due to early user close
8364 connections aborted due to timeout
TCPSACKDiscard: 27
TCPDSACKIgnoredOld: 21
TCPDSACKIgnoredNoUndo: 236533
TCPSpuriousRTOs: 1654
TCPSackShiftFallback: 237468
TCPRcvCoalesce: 8730449
TCPOFOQueue: 369700
TCPOFOMerge: 1804
TCPChallengeACK: 2351
TCPSYNChallenge: 131
TCPFastOpenCookieReqd: 10
TCPSpuriousRtxHostQueues: 1570
TCPFromZeroWindowAdv: 8
TCPToZeroWindowAdv: 8
TCPWantZeroWindowAdv: 288
TCPSynRetrans: 459990
TCPOrigDataSent: 38844156
TCPHystartTrainDetect: 90
TCPHystartTrainCwnd: 2776
TCPHystartDelayDetect: 164
TCPHystartDelayCwnd: 7097
TCPACKSkippedSynRecv: 477
TCPACKSkippedPAWS: 150
TCPACKSkippedSeq: 1364
TCPACKSkippedTimeWait: 89
TCPACKSkippedChallenge: 37
IpExt:
InNoRoutes: 5
InMcastPkts: 200627
InOctets: 8033825866
OutOctets: 15832341267
InMcastOctets: 7222572
InNoECTPkts: 87780970
InECT1Pkts: 256
InECT0Pkts: 102401
InCEPkts: 21831显示监听的套接口
# netstat -l
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 0 0.0.0.0:cddbp 0.0.0.0:* LISTEN
tcp 0 0 VM_0_15_centos:smtp 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:sunwebadmins 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:http 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:ftp 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:ssh 0.0.0.0:* LISTEN
tcp6 0 0 VM_0_15_centos:smtp [::]:* LISTEN
tcp6 0 0 [::]:mysql [::]:* LISTEN
tcp6 0 0 [::]:ftp [::]:* LISTEN
udp 0 0 0.0.0.0:bootpc 0.0.0.0:*
udp 0 0 VM_0_15_centos:ntp 0.0.0.0:*
udp 0 0 VM_0_15_centos:ntp 0.0.0.0:*
udp 0 0 0.0.0.0:56631 0.0.0.0:*
udp6 0 0 VM_0_15_centos:ntp [::]:*
udp6 0 0 VM_0_15_centos:ntp [::]:*
Active UNIX domain sockets (only servers)
Proto RefCnt Flags Type State I-Node Path
unix 2 [ ACC ] STREAM LISTENING 10758 /run/lvm/lvmetad.socket
unix 2 [ ACC ] STREAM LISTENING 7457 /run/systemd/journal/stdout
unix 2 [ ACC ] STREAM LISTENING 38969 public/pickup
unix 2 [ ACC ] STREAM LISTENING 38973 public/cleanup
...