netstat命令用於顯示與IP、TCP、UDP和ICMP協定相關的統計資料，一般用於檢驗本機各埠的網路連線情況。netstat是在核心中存取網路及相關資訊的程式，它能提供TCP連線，TCP和UDP監聽，進程記憶體管理的相關報告。
如果計算機有時候接收到的資料報導致出錯資料或故障，不必感到奇怪，TCP/IP可以容許這些型別的錯誤，並能夠自動重發資料報。但如果累計的出錯情況數目占到所接收的IP資料報相當大的百分比，或者它的數目正迅速增加，那麼就應該使用netstat查一查為什麼會出現這些情況了。
netstat [-acCeFghilMnNoprstuvVwx][-A<網路型別>][--ip]
netstat用於顯示與IP、TCP、UDP和ICMP協定相關的統計資料，一般用於檢驗本機各埠的網路連線情況。
-a或–all 顯示所有連線中的Socket。-A<網路型別>或–<網路型別> 列出該網路型別連線中的相關地址。-c或–continuous 持續列出網路狀態。-C或–cache 顯示路由器組態的快取資訊。-e或–extend 顯示網路其他相關資訊。-F或–fib 顯示FIB。-g或–groups 顯示多重廣播功能群組組員名單。-h或–help 線上幫助。-i或–interfaces 顯示網路介面資訊表單。-l或–listening 顯示監控中的伺服器的Socket。-M或–masquerade 顯示偽裝的網路連線。-n或–numeric 直接使用IP地址，而不通過域名伺服器。-N或–netlink或–symbolic 顯示網路硬體外圍裝置的符號連線名稱。-o或–timers 顯示計時器。-p或–programs 顯示正在使用Socket的程式識別碼和程式名稱。-r或–route 顯示Routing Table。-s或–statistice 顯示網路工作資訊統計表。-t或–tcp 顯示TCP傳輸協定的連線狀況。-u或–udp 顯示UDP傳輸協定的連線狀況。-v或–verbose 顯示指令執行過程。-V或–version 顯示版本資訊。-w或–raw 顯示RAW傳輸協定的連線狀況。-x或–unix 此引數的效果和指定」-A unix」引數相同。–ip或–inet 此引數的效果和指定」-A inet」引數相同。命令：
netstat
輸出：
[yiibai@localhost ~]$ netstat
Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 0 localhost.localdoma:ssh 192.168.0.5:54835 ESTABLISHED
Active UNIX domain sockets (w/o servers)
Proto RefCnt Flags Type State I-Node Path
unix 2 [ ] DGRAM 13100 /run/systemd/shutdownd
unix 2 [ ] DGRAM 8385 /run/systemd/notify
unix 2 [ ] DGRAM 8387 /run/systemd/cgroups-agent
unix 5 [ ] DGRAM 8398 /run/systemd/journal/socket
unix 13 [ ] DGRAM 8400 /dev/log
unix 3 [ ] STREAM CONNECTED 19870
unix 3 [ ] STREAM CONNECTED 19850
unix 3 [ ] STREAM CONNECTED 19871
unix 3 [ ] STREAM CONNECTED 19830
unix 3 [ ] STREAM CONNECTED 16422
unix 3 [ ] STREAM CONNECTED 19852
unix 3 [ ] STREAM CONNECTED 16423 /var/run/dbus/system_bus_socket
unix 3 [ ] STREAM CONNECTED 19873
unix 3 [ ] STREAM CONNECTED 19874
unix 3 [ ] STREAM CONNECTED 15501
unix 3 [ ] STREAM CONNECTED 19847
unix 3 [ ] STREAM CONNECTED 19821
unix 3 [ ] STREAM CONNECTED 19849
unix 3 [ ] STREAM CONNECTED 19844
unix 3 [ ] STREAM CONNECTED 19820
unix 3 [ ] STREAM CONNECTED 19876
unix 3 [ ] STREAM CONNECTED 19833
unix 3 [ ] STREAM CONNECTED 19877
unix 2 [ ] DGRAM 16501
unix 3 [ ] STREAM CONNECTED 16576
unix 3 [ ] STREAM CONNECTED 19879
unix 3 [ ] STREAM CONNECTED 19829
unix 2 [ ] DGRAM 80277
unix 3 [ ] STREAM CONNECTED 19880
unix 3 [ ] STREAM CONNECTED 15803 /run/systemd/journal/stdout
unix 3 [ ] STREAM CONNECTED 19882
unix 3 [ ] STREAM CONNECTED 19263
unix 3 [ ] STREAM CONNECTED 19883
unix 3 [ ] STREAM CONNECTED 19853
unix 2 [ ] DGRAM 16412
unix 3 [ ] STREAM CONNECTED 19855
unix 3 [ ] STREAM CONNECTED 15802
unix 3 [ ] STREAM CONNECTED 19856
unix 3 [ ] STREAM CONNECTED 15502 /run/systemd/journal/stdout
unix 3 [ ] STREAM CONNECTED 80280
unix 3 [ ] STREAM CONNECTED 19858
unix 3 [ ] STREAM CONNECTED 19859
unix 3 [ ] STREAM CONNECTED 80281
unix 3 [ ] STREAM CONNECTED 19861
unix 3 [ ] STREAM CONNECTED 19843
unix 3 [ ] STREAM CONNECTED 19862
unix 3 [ ] STREAM CONNECTED 15457
unix 3 [ ] STREAM CONNECTED 19864
unix 3 [ ] STREAM CONNECTED 15613 /var/run/dbus/system_bus_socket
unix 3 [ ] STREAM CONNECTED 19865
unix 3 [ ] STREAM CONNECTED 19846
unix 2 [ ] DGRAM 80112
unix 3 [ ] STREAM CONNECTED 19867
unix 3 [ ] STREAM CONNECTED 16577 /var/run/dbus/system_bus_socket
unix 3 [ ] STREAM CONNECTED 19868
unix 2 [ ] DGRAM 15509
unix 3 [ ] STREAM CONNECTED 19264 /var/run/dbus/system_bus_socket
unix 3 [ ] STREAM CONNECTED 16129 /var/run/dbus/system_bus_socket
unix 3 [ ] STREAM CONNECTED 13393
unix 3 [ ] STREAM CONNECTED 19837
unix 2 [ ] DGRAM 13285
unix 3 [ ] STREAM CONNECTED 13530 /run/systemd/journal/stdout
unix 2 [ ] DGRAM 19784
unix 3 [ ] STREAM CONNECTED 16379 /run/systemd/journal/stdout
unix 3 [ ] STREAM CONNECTED 16160
unix 3 [ ] STREAM CONNECTED 13796 /run/systemd/journal/stdout
unix 3 [ ] STREAM CONNECTED 15732 /run/systemd/journal/stdout
unix 3 [ ] STREAM CONNECTED 15611
unix 3 [ ] STREAM CONNECTED 13777
unix 2 [ ] DGRAM 20011
unix 3 [ ] STREAM CONNECTED 16106 /run/systemd/journal/stdout
unix 3 [ ] STREAM CONNECTED 19840
......
說明：
從整體上看，netstat的輸出結果可以分為兩個部分：
一個是Active Internet connections，稱為有源TCP連線，其中」Recv-Q」和」Send-Q」指的是接收佇列和傳送佇列。這些數位一般都應該是0。如果不是則表示軟體包正在佇列中堆積。這種情況只能在非常少的情況見到。
另一個是Active UNIX domain sockets，稱為有源Unix域套介面(和網路通訊端一樣，但是只能用於本機通訊，效能可以提高一倍)。
Proto顯示連線使用的協定,RefCnt表示連線到本套介面上的進程號,Types顯示套介面的型別,State顯示套介面當前的狀態,Path表示連線到套介面的其它進程使用的路徑名。
套介面型別：
-t ：TCP-u ：UDP-raw ：RAW型別--unix ：UNIX域型別--ax25 ：AX25型別--ipx ：ipx型別--netrom ：netrom型別狀態說明：
LISTEN：偵聽來自遠方的TCP埠的連線請求SYN-SENT：再傳送連線請求後等待匹配的連線請求(如果有大量這樣的狀態包，檢查是否中招了)SYN-RECEIVED：再收到和傳送一個連線請求後等待對方對連線請求的確認(如有大量此狀態，估計被flood攻擊了)ESTABLISHED：代表一個開啟的連線FIN-WAIT-1：等待遠端TCP連線中斷請求，或先前的連線中斷請求的確認FIN-WAIT-2：從遠端TCP等待連線中斷請求CLOSE-WAIT：等待從本地使用者發來的連線中斷請求CLOSING：等待遠端TCP對連線中斷的確認LAST-ACK：等待原來的發向遠端TCP的連線中斷請求的確認(不是什麼好東西，此項出現，檢查是否被攻擊)TIME-WAIT：等待足夠的時間以確保遠端TCP接收到連線中斷請求的確認CLOSED：沒有任何連線狀態命令：
netstat -a
輸出：
[yiibai@localhost ~]$ netstat -a
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 0 0.0.0.0:ssh 0.0.0.0:* LISTEN
tcp 0 0 localhost:smtp 0.0.0.0:* LISTEN
tcp 0 52 localhost.localdoma:ssh 192.168.0.5:54835 ESTABLISHED
tcp6 0 0 [::]:ssh [::]:* LISTEN
tcp6 0 0 localhost:smtp [::]:* LISTEN
udp 0 0 0.0.0.0:trnsprntproxy 0.0.0.0:*
udp 0 0 localhost:323 0.0.0.0:*
udp 0 0 0.0.0.0:bootpc 0.0.0.0:*
udp6 0 0 [::]:rnm [::]:*
udp6 0 0 localhost:323 [::]:*
raw6 0 0 [::]:ipv6-icmp [::]:* 7
Active UNIX domain sockets (servers and established)
Proto RefCnt Flags Type State I-Node Path
unix 2 [ ACC ] STREAM LISTENING 12805 /run/lvm/lvmpolld.socket
unix 2 [ ACC ] SEQPACKET LISTENING 12811 /run/udev/control
unix 2 [ ACC ] STREAM LISTENING 12827 /run/lvm/lvmetad.socket
unix 2 [ ] DGRAM 13100 /run/systemd/shutdownd
unix 2 [ ACC ] STREAM LISTENING 19872 public/showq
unix 2 [ ACC ] STREAM LISTENING 19842 private/rewrite
unix 2 [ ACC ] STREAM LISTENING 15231 /var/run/dbus/system_bus_socket
unix 2 [ ACC ] STREAM LISTENING 19845 private/bounce
unix 2 [ ACC ] STREAM LISTENING 19848 private/defer
unix 2 [ ACC ] STREAM LISTENING 19851 private/trace
unix 2 [ ACC ] STREAM LISTENING 19854 private/verify
unix 2 [ ACC ] STREAM LISTENING 19860 private/proxymap
unix 2 [ ACC ] STREAM LISTENING 19863 private/proxywrite
unix 2 [ ACC ] STREAM LISTENING 19866 private/smtp
unix 2 [ ACC ] STREAM LISTENING 19869 private/relay
unix 2 [ ACC ] STREAM LISTENING 19875 private/error
unix 2 [ ACC ] STREAM LISTENING 19878 private/retry
unix 2 [ ACC ] STREAM LISTENING 19881 private/discard
unix 2 [ ACC ] STREAM LISTENING 19884 private/local
unix 2 [ ACC ] STREAM LISTENING 19887 private/virtual
unix 2 [ ACC ] STREAM LISTENING 19890 private/lmtp
unix 2 [ ACC ] STREAM LISTENING 19893 private/anvil
unix 2 [ ACC ] STREAM LISTENING 19896 private/scache
unix 2 [ ACC ] STREAM LISTENING 19822 public/pickup
unix 2 [ ACC ] STREAM LISTENING 19832 public/cleanup
unix 2 [ ACC ] STREAM LISTENING 19835 public/qmgr
unix 2 [ ACC ] STREAM LISTENING 19857 public/flush
unix 2 [ ACC ] STREAM LISTENING 17836 /var/run/NetworkManager/private-dhcp
unix 2 [ ] DGRAM 8385 /run/systemd/notify
unix 2 [ ] DGRAM 8387 /run/systemd/cgroups-agent
unix 2 [ ACC ] STREAM LISTENING 19839 private/tlsmgr
......
說明：顯示一個所有的有效連線資訊列表，包括已建立的連線(ESTABLISHED)，也包括監聽連線請(LISTENING)的那些連線。
命令：
netstat -nu
輸出：
[yiibai@localhost ~]$ netstat -nu
Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address Foreign Address State
[yiibai@localhost ~]$
命令：
netstat -apu
輸出：
[yiibai@localhost ~]$ netstat -apu
(No info could be read for "-p": geteuid()=1000 but you should be root.)
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:trnsprntproxy 0.0.0.0:* -
udp 0 0 localhost:323 0.0.0.0:* -
udp 0 0 0.0.0.0:bootpc 0.0.0.0:* -
udp6 0 0 [::]:rnm [::]:* -
udp6 0 0 localhost:323 [::]:* -
[yiibai@localhost ~]$
命令：
netstat -i
輸出：
[yiibai@localhost ~]$ netstat -i
Kernel Interface table
Iface MTU RX-OK RX-ERR RX-DRP RX-OVR TX-OK TX-ERR TX-DRP TX-OVR Flg
ens33 1500 63831 0 0 0 6313 0 0 0 BMRU
lo 65536 19 0 0 0 19 0 0 0 LRU
[yiibai@localhost ~]$
命令：
netstat -g
輸出：
[yiibai@localhost ~]$ netstat -g
IPv6/IPv4 Group Memberships
Interface RefCnt Group
--------------- ------ ---------------------
lo 1 all-systems.mcast.net
ens33 1 all-systems.mcast.net
lo 1 ff02::1
lo 1 ff01::1
ens33 1 ff02::1:ff35:dd8c
ens33 1 ff02::1
ens33 1 ff01::1
[yiibai@localhost ~]$
命令：
netstat -s
輸出：
[yiibai@localhost ~]$ netstat -s
Ip:
28607 total packets received
0 forwarded
0 incoming packets discarded
4123 incoming packets delivered
4143 requests sent out
50 dropped because of missing route
Icmp:
767 ICMP messages received
402 input ICMP message failed.
ICMP input histogram:
destination unreachable: 152
timeout in transit: 164
echo requests: 402
echo replies: 49
467 ICMP messages sent
0 ICMP messages failed
ICMP output histogram:
destination unreachable: 9
echo request: 458
IcmpMsg:
InType0: 49
InType3: 152
InType8: 402
InType11: 164
OutType3: 9
OutType8: 458
Tcp:
3 active connections openings
3 passive connection openings
0 failed connection attempts
0 connection resets received
1 connections established
2880 segments received
2548 segments send out
0 segments retransmited
0 bad segments received.
0 resets sent
Udp:
474 packets received
2 packets to unknown port received.
0 packet receive errors
1160 packets sent
0 receive buffer errors
0 send buffer errors
UdpLite:
TcpExt:
3 TCP sockets finished time wait in fast timer
11 delayed acks sent
1 delayed acks further delayed because of locked socket
1 packets directly queued to recvmsg prequeue.
1139 packet headers predicted
441 acknowledgments not containing data payload received
1356 predicted acknowledgments
IPReversePathFilter: 1
TCPRcvCoalesce: 69
TCPOrigDataSent: 2427
IpExt:
InNoRoutes: 5
InMcastPkts: 435
InBcastPkts: 24444
OutBcastPkts: 402
InOctets: 2452235
OutOctets: 539407
InMcastOctets: 13920
InBcastOctets: 2027384
OutBcastOctets: 33768
InNoECTPkts: 28642
[yiibai@localhost ~]$
說明：
按照各個協定分別顯示其統計資料。如果我們的應用程式(如Web瀏覽器)執行速度比較慢，或者不能顯示Web頁之類的資料，那麼我們就可以用本選項來檢視一下所顯示的資訊。我們需要仔細檢視統計資料的各行，找到出錯的關鍵字，進而確定問題所在。
命令：
netstat -l
輸出：
[yiibai@localhost ~]$ netstat -l
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 0 0.0.0.0:ssh 0.0.0.0:* LISTEN
tcp 0 0 localhost:smtp 0.0.0.0:* LISTEN
tcp6 0 0 [::]:ssh [::]:* LISTEN
tcp6 0 0 localhost:smtp [::]:* LISTEN
udp 0 0 0.0.0.0:trnsprntproxy 0.0.0.0:*
udp 0 0 localhost:323 0.0.0.0:*
udp 0 0 0.0.0.0:bootpc 0.0.0.0:*
udp6 0 0 [::]:rnm [::]:*
udp6 0 0 localhost:323 [::]:*
raw6 0 0 [::]:ipv6-icmp [::]:* 7
Active UNIX domain sockets (only servers)
Proto RefCnt Flags Type State I-Node Path
unix 2 [ ACC ] STREAM LISTENING 12805 /run/lvm/lvmpolld.socket
unix 2 [ ACC ] SEQPACKET LISTENING 12811 /run/udev/control
unix 2 [ ACC ] STREAM LISTENING 12827 /run/lvm/lvmetad.socket
unix 2 [ ACC ] STREAM LISTENING 19872 public/showq
unix 2 [ ACC ] STREAM LISTENING 19842 private/rewrite
unix 2 [ ACC ] STREAM LISTENING 15231 /var/run/dbus/system_bus_socket
unix 2 [ ACC ] STREAM LISTENING 19845 private/bounce
unix 2 [ ACC ] STREAM LISTENING 19848 private/defer
unix 2 [ ACC ] STREAM LISTENING 19851 private/trace
unix 2 [ ACC ] STREAM LISTENING 19854 private/verify
unix 2 [ ACC ] STREAM LISTENING 19860 private/proxymap
unix 2 [ ACC ] STREAM LISTENING 19863 private/proxywrite
unix 2 [ ACC ] STREAM LISTENING 19866 private/smtp
unix 2 [ ACC ] STREAM LISTENING 19869 private/relay
unix 2 [ ACC ] STREAM LISTENING 19875 private/error
unix 2 [ ACC ] STREAM LISTENING 19878 private/retry
unix 2 [ ACC ] STREAM LISTENING 19881 private/discard
unix 2 [ ACC ] STREAM LISTENING 19884 private/local
unix 2 [ ACC ] STREAM LISTENING 19887 private/virtual
unix 2 [ ACC ] STREAM LISTENING 19890 private/lmtp
unix 2 [ ACC ] STREAM LISTENING 19893 private/anvil
unix 2 [ ACC ] STREAM LISTENING 19896 private/scache
unix 2 [ ACC ] STREAM LISTENING 19822 public/pickup
unix 2 [ ACC ] STREAM LISTENING 19832 public/cleanup
unix 2 [ ACC ] STREAM LISTENING 19835 public/qmgr
unix 2 [ ACC ] STREAM LISTENING 19857 public/flush
unix 2 [ ACC ] STREAM LISTENING 17836 /var/run/NetworkManager/private-dhcp
unix 2 [ ACC ] STREAM LISTENING 19839 private/tlsmgr
unix 2 [ ACC ] STREAM LISTENING 8395 /run/systemd/journal/stdout
unix 2 [ ACC ] STREAM LISTENING 12794 /run/systemd/private
[yiibai@localhost ~]$
命令：
netstat -n
輸出：
[yiibai@localhost ~]$ netstat -n
Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 52 192.168.0.197:22 192.168.0.5:54835 ESTABLISHED
Active UNIX domain sockets (w/o servers)
Proto RefCnt Flags Type State I-Node Path
unix 2 [ ] DGRAM 13100 /run/systemd/shutdownd
unix 2 [ ] DGRAM 8385 /run/systemd/notify
unix 2 [ ] DGRAM 8387 /run/systemd/cgroups-agent
unix 5 [ ] DGRAM 8398 /run/systemd/journal/socket
unix 13 [ ] DGRAM 8400 /dev/log
unix 3 [ ] STREAM CONNECTED 19870
unix 3 [ ] STREAM CONNECTED 19850
unix 3 [ ] STREAM CONNECTED 19871
unix 3 [ ] STREAM CONNECTED 19830
unix 3 [ ] STREAM CONNECTED 16422
unix 3 [ ] STREAM CONNECTED 19852
unix 3 [ ] STREAM CONNECTED 16423 /var/run/dbus/system_bus_socket
unix 3 [ ] STREAM CONNECTED 19873
unix 3 [ ] STREAM CONNECTED 19874
unix 3 [ ] STREAM CONNECTED 15501
unix 3 [ ] STREAM CONNECTED 19847
unix 3 [ ] STREAM CONNECTED 19821
unix 3 [ ] STREAM CONNECTED 19849
unix 3 [ ] STREAM CONNECTED 19844
unix 3 [ ] STREAM CONNECTED 19820
unix 3 [ ] STREAM CONNECTED 19876
unix 3 [ ] STREAM CONNECTED 19833
unix 3 [ ] STREAM CONNECTED 19877
unix 2 [ ] DGRAM 16501
unix 3 [ ] STREAM CONNECTED 16576
unix 3 [ ] STREAM CONNECTED 19879
unix 3 [ ] STREAM CONNECTED 19829
unix 2 [ ] DGRAM 80277
unix 3 [ ] STREAM CONNECTED 19880
unix 3 [ ] STREAM CONNECTED 15803 /run/systemd/journal/stdout
unix 3 [ ] STREAM CONNECTED 19882
unix 3 [ ] STREAM CONNECTED 19263
unix 3 [ ] STREAM CONNECTED 19883
unix 3 [ ] STREAM CONNECTED 19853
unix 2 [ ] DGRAM 16412
unix 3 [ ] STREAM CONNECTED 19855
unix 3 [ ] STREAM CONNECTED 15802
unix 3 [ ] STREAM CONNECTED 19856
unix 3 [ ] STREAM CONNECTED 15502 /run/systemd/journal/stdout
unix 3 [ ] STREAM CONNECTED 80280
unix 3 [ ] STREAM CONNECTED 19858
unix 3 [ ] STREAM CONNECTED 19859
unix 3 [ ] STREAM CONNECTED 80281
unix 3 [ ] STREAM CONNECTED 19861
unix 3 [ ] STREAM CONNECTED 19843
unix 3 [ ] STREAM CONNECTED 19862
unix 3 [ ] STREAM CONNECTED 15457
unix 3 [ ] STREAM CONNECTED 19864
unix 3 [ ] STREAM CONNECTED 15613 /var/run/dbus/system_bus_socket
unix 3 [ ] STREAM CONNECTED 19865
unix 3 [ ] STREAM CONNECTED 19846
unix 2 [ ] DGRAM 80112
unix 3 [ ] STREAM CONNECTED 19867
unix 3 [ ] STREAM CONNECTED 16577 /var/run/dbus/system_bus_socket
unix 3 [ ] STREAM CONNECTED 19868
unix 2 [ ] DGRAM 15509
unix 3 [ ] STREAM CONNECTED 19264 /var/run/dbus/system_bus_socket
unix 3 [ ] STREAM CONNECTED 16129 /var/run/dbus/system_bus_socket
unix 3 [ ] STREAM CONNECTED 13393
unix 3 [ ] STREAM CONNECTED 19837
unix 2 [ ] DGRAM 13285
unix 3 [ ] STREAM CONNECTED 13530 /run/systemd/journal/stdout
unix 2 [ ] DGRAM 19784
unix 3 [ ] STREAM CONNECTED 16379 /run/systemd/journal/stdout
unix 3 [ ] STREAM CONNECTED 16160
unix 3 [ ] STREAM CONNECTED 13796 /run/systemd/journal/stdout
unix 3 [ ] STREAM CONNECTED 15732 /run/systemd/journal/stdout
unix 3 [ ] STREAM CONNECTED 15611
unix 3 [ ] STREAM CONNECTED 13777
unix 2 [ ] DGRAM 20011
unix 3 [ ] STREAM CONNECTED 16106 /run/systemd/journal/stdout
unix 3 [ ] STREAM CONNECTED 19840
unix 2 [ ] DGRAM 16231
unix 3 [ ] STREAM CONNECTED 16105
unix 3 [ ] STREAM CONNECTED 16320
unix 3 [ ] STREAM CONNECTED 19885
unix 3 [ ] DGRAM 13816
unix 3 [ ] STREAM CONNECTED 18433 /run/systemd/journal/stdout
unix 3 [ ] STREAM CONNECTED 16321 /var/run/dbus/system_bus_socket
unix 3 [ ] STREAM CONNECTED 19886
unix 3 [ ] STREAM CONNECTED 16161 /var/run/dbus/system_bus_socket
unix 3 [ ] STREAM CONNECTED 16378
unix 3 [ ] STREAM CONNECTED 19888
unix 3 [ ] STREAM CONNECTED 15612
unix 3 [ ] STREAM CONNECTED 18432
unix 3 [ ] STREAM CONNECTED 19889
unix 2 [ ] DGRAM 16204
unix 3 [ ] STREAM CONNECTED 15731
unix 3 [ ] STREAM CONNECTED 19834
unix 3 [ ] STREAM CONNECTED 19891
unix 3 [ ] STREAM CONNECTED 19841
unix 3 [ ] STREAM CONNECTED 19836
unix 2 [ ] DGRAM 79889
unix 3 [ ] STREAM CONNECTED 19892
unix 2 [ ] DGRAM 16133
unix 3 [ ] STREAM CONNECTED 15152
unix 3 [ ] STREAM CONNECTED 16128
unix 3 [ ] STREAM CONNECTED 19894
unix 3 [ ] STREAM CONNECTED 19895
unix 3 [ ] STREAM CONNECTED 15153
unix 3 [ ] STREAM CONNECTED 19897
unix 3 [ ] STREAM CONNECTED 19898
unix 3 [ ] DGRAM 13817
unix 2 [ ] DGRAM 13797
unix 2 [ ] DGRAM 15143
[yiibai@localhost ~]$
命令：
netstat -e
輸出：
[yiibai@localhost ~]$ netstat -e
Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address Foreign Address State User Inode
tcp 0 52 localhost.localdoma:ssh 192.168.0.5:54835 ESTABLISHED root 80161
Active UNIX domain sockets (w/o servers)
Proto RefCnt Flags Type State I-Node Path
unix 2 [ ] DGRAM 13100 /run/systemd/shutdownd
unix 2 [ ] DGRAM 8385 /run/systemd/notify
unix 2 [ ] DGRAM 8387 /run/systemd/cgroups-agent
unix 5 [ ] DGRAM 8398 /run/systemd/journal/socket
unix 13 [ ] DGRAM 8400 /dev/log
unix 3 [ ] STREAM CONNECTED 19870
unix 3 [ ] STREAM CONNECTED 19850
unix 3 [ ] STREAM CONNECTED 19871
unix 3 [ ] STREAM CONNECTED 19830
unix 3 [ ] STREAM CONNECTED 16422
unix 3 [ ] STREAM CONNECTED 19852
unix 3 [ ] STREAM CONNECTED 16423 /var/run/dbus/system_bus_socket
unix 3 [ ] STREAM CONNECTED 19873
unix 3 [ ] STREAM CONNECTED 19874
unix 3 [ ] STREAM CONNECTED 15501
unix 3 [ ] STREAM CONNECTED 19847
unix 3 [ ] STREAM CONNECTED 19821
unix 3 [ ] STREAM CONNECTED 19849
unix 3 [ ] STREAM CONNECTED 19844
unix 3 [ ] STREAM CONNECTED 19820
unix 3 [ ] STREAM CONNECTED 19876
unix 3 [ ] STREAM CONNECTED 19833
unix 3 [ ] STREAM CONNECTED 19877
unix 2 [ ] DGRAM 16501
unix 3 [ ] STREAM CONNECTED 16576
unix 3 [ ] STREAM CONNECTED 19879
unix 3 [ ] STREAM CONNECTED 19829
unix 2 [ ] DGRAM 80277
unix 3 [ ] STREAM CONNECTED 19880
unix 3 [ ] STREAM CONNECTED 15803 /run/systemd/journal/stdout
unix 3 [ ] STREAM CONNECTED 19882
unix 3 [ ] STREAM CONNECTED 19263
unix 3 [ ] STREAM CONNECTED 19883
unix 3 [ ] STREAM CONNECTED 19853
unix 2 [ ] DGRAM 16412
unix 3 [ ] STREAM CONNECTED 19855
unix 3 [ ] STREAM CONNECTED 15802
unix 3 [ ] STREAM CONNECTED 19856
unix 3 [ ] STREAM CONNECTED 15502 /run/systemd/journal/stdout
unix 3 [ ] STREAM CONNECTED 80280
unix 3 [ ] STREAM CONNECTED 19858
unix 3 [ ] STREAM CONNECTED 19859
unix 3 [ ] STREAM CONNECTED 80281
unix 3 [ ] STREAM CONNECTED 19861
unix 3 [ ] STREAM CONNECTED 19843
unix 3 [ ] STREAM CONNECTED 19862
unix 3 [ ] STREAM CONNECTED 15457
unix 3 [ ] STREAM CONNECTED 19864
unix 3 [ ] STREAM CONNECTED 15613 /var/run/dbus/system_bus_socket
unix 3 [ ] STREAM CONNECTED 19865
unix 3 [ ] STREAM CONNECTED 19846
unix 2 [ ] DGRAM 80112
unix 3 [ ] STREAM CONNECTED 19867
unix 3 [ ] STREAM CONNECTED 16577 /var/run/dbus/system_bus_socket
unix 3 [ ] STREAM CONNECTED 19868
unix 2 [ ] DGRAM 15509
unix 3 [ ] STREAM CONNECTED 19264 /var/run/dbus/system_bus_socket
unix 3 [ ] STREAM CONNECTED 16129 /var/run/dbus/system_bus_socket
unix 3 [ ] STREAM CONNECTED 13393
unix 3 [ ] STREAM CONNECTED 19837
unix 2 [ ] DGRAM 13285
unix 3 [ ] STREAM CONNECTED 13530 /run/systemd/journal/stdout
unix 2 [ ] DGRAM 19784
unix 3 [ ] STREAM CONNECTED 16379 /run/systemd/journal/stdout
unix 3 [ ] STREAM CONNECTED 16160
unix 3 [ ] STREAM CONNECTED 13796 /run/systemd/journal/stdout
unix 3 [ ] STREAM CONNECTED 15732 /run/systemd/journal/stdout
unix 3 [ ] STREAM CONNECTED 15611
unix 3 [ ] STREAM CONNECTED 13777
unix 2 [ ] DGRAM 20011
unix 3 [ ] STREAM CONNECTED 16106 /run/systemd/journal/stdout
unix 3 [ ] STREAM CONNECTED 19840
unix 2 [ ] DGRAM 16231
unix 3 [ ] STREAM CONNECTED 16105
unix 3 [ ] STREAM CONNECTED 16320
unix 3 [ ] STREAM CONNECTED 19885
unix 3 [ ] DGRAM 13816
unix 3 [ ] STREAM CONNECTED 18433 /run/systemd/journal/stdout
unix 3 [ ] STREAM CONNECTED 16321 /var/run/dbus/system_bus_socket
unix 3 [ ] STREAM CONNECTED 19886
unix 3 [ ] STREAM CONNECTED 16161 /var/run/dbus/system_bus_socket
unix 3 [ ] STREAM CONNECTED 16378
unix 3 [ ] STREAM CONNECTED 19888
unix 3 [ ] STREAM CONNECTED 15612
unix 3 [ ] STREAM CONNECTED 18432
unix 3 [ ] STREAM CONNECTED 19889
unix 2 [ ] DGRAM 16204
unix 3 [ ] STREAM CONNECTED 15731
unix 3 [ ] STREAM CONNECTED 19834
unix 3 [ ] STREAM CONNECTED 19891
unix 3 [ ] STREAM CONNECTED 19841
unix 3 [ ] STREAM CONNECTED 19836
unix 2 [ ] DGRAM 79889
unix 3 [ ] STREAM CONNECTED 19892
unix 2 [ ] DGRAM 16133
unix 3 [ ] STREAM CONNECTED 15152
unix 3 [ ] STREAM CONNECTED 16128
unix 3 [ ] STREAM CONNECTED 19894
unix 3 [ ] STREAM CONNECTED 19895
unix 3 [ ] STREAM CONNECTED 15153
unix 3 [ ] STREAM CONNECTED 19897
unix 3 [ ] STREAM CONNECTED 19898
unix 3 [ ] DGRAM 13817
unix 2 [ ] DGRAM 13797
unix 2 [ ] DGRAM 15143
[yiibai@localhost ~]$
說明：
用於顯示關於乙太網的統計資料。它列出的專案包括傳送的資料報的總位元組數、錯誤數、刪除數、資料報的數量和廣播的數量。這些統計資料既有傳送的資料報數量，也有接收的資料報數量。這個選項可以用來統計一些基本的網路流量)
命令：
netstat -r
輸出：
[yiibai@localhost ~]$ netstat -r
Kernel IP routing table
Destination Gateway Genmask Flags MSS Window irtt Iface
default gateway 0.0.0.0 UG 0 0 0 ens33
192.168.0.0 0.0.0.0 255.255.255.0 U 0 0 0 ens33
[yiibai@localhost ~]$
命令：
netstat -at
輸出：
[yiibai@localhost ~]$ netstat -at
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 0 0.0.0.0:ssh 0.0.0.0:* LISTEN
tcp 0 0 localhost:smtp 0.0.0.0:* LISTEN
tcp 0 52 localhost.localdoma:ssh 192.168.0.5:54835 ESTABLISHED
tcp6 0 0 [::]:ssh [::]:* LISTEN
tcp6 0 0 localhost:smtp [::]:* LISTEN
[yiibai@localhost ~]$
命令：
netstat -a | awk '/^tcp/ {++S[$NF]} END {for(a in S) print a, S[a]}'
輸出：
[yiibai@localhost ~]$ netstat -a | awk '/^tcp/ {++S[$NF]} END {for(a in S) print a, S[a]}'
LISTEN 4
ESTABLISHED 1
[yiibai@localhost ~]$
命令：
netstat -nat |awk '{print $6}'|sort|uniq -c
輸出：
命令：
netstat -nat | grep "192.168.120.20:16067" |awk '{print $5}'|awk -F: '{print $4}'|sort|uniq -c|sort -nr|head -20
輸出：
[yiibai@localhost ~]$ netstat -nat |awk '{print $6}'|sort|uniq -c
1 established)
1 ESTABLISHED
1 Foreign
4 LISTEN
[yiibai@localhost ~]$
命令：
netstat -ap | grep ssh
輸出：
[yiibai@localhost ~]$ netstat -ap | grep ssh
(No info could be read for "-p": geteuid()=1000 but you should be root.)
tcp 0 0 0.0.0.0:ssh 0.0.0.0:* LISTEN -
tcp 0 52 localhost.localdoma:ssh 192.168.0.5:54835 ESTABLISHED -
tcp6 0 0 [::]:ssh [::]:* LISTEN -
[yiibai@localhost ~]$
命令：
netstat -pt
輸出：
[yiibai@localhost ~]$ netstat -pt
(No info could be read for "-p": geteuid()=1000 but you should be root.)
Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp 0 52 localhost.localdoma:ssh 192.168.0.5:54835 ESTABLISHED -
[yiibai@localhost ~]$
說明：netstat -p可以與其它開關一起使用，就可以新增 「PID/進程名稱」 到 netstat 輸出中，這樣 debugging 的時候可以很方便的發現特定埠執行的程式。
命令：
netstat -anpt | grep ':16160'
輸出：
[root@localhost yiibai]# netstat -anpt | grep ':16160'
[root@localhost yiibai]# netstat -anpt | grep ':22'
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 1032/sshd
tcp 0 52 192.168.0.197:22 192.168.0.5:54835 ESTABLISHED 4039/sshd: yiibai [
tcp6 0 0 :::22 :::* LISTEN 1032/sshd
[root@localhost yiibai]#
說明：
執行在埠22的進程id為1032，再通過ps命令就可以找到具體的應用程式了。