Linux 网络管理的 20 个 Netstat 命令
netstat（网络统计）是一个命令行工具，用于监控传入和传出的网络连接以及查看路由表、接口统计信息等。
netstat 可在所有类 Unix 操作系统上使用，也可在 Windows 操作系统 上使用。它在网络故障排除和性能测量方面非常有用。
netstat是最基本的网络服务调试工具之一，可以告诉您哪些端口打开以及是否有程序正在侦听端口。
更新：Linux netstat 命令被新的 ss 命令取代，该命令能够显示更多有关网络连接的信息，并且比旧的 netstat 命令快得多。
netstat 工具对于 Linux 网络管理员和系统管理员监控和排除网络相关问题并确定网络流量性能非常重要且非常有用。
本文展示了 netstat 命令的用法及其示例，这些示例在日常操作中可能有用。
1.列出所有TCP和UDP连接的监听端口
使用 netstat -a 选项列出所有端口（TCP 和 UDP）。
netstat -a | more
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 0 *:sunrpc *:* LISTEN
tcp 0 52 192.168.0.2:ssh 192.168.0.1:egs ESTABLISHED
tcp 1 0 192.168.0.2:59292 www.gov.com:http CLOSE_WAIT
tcp 0 0 localhost:smtp *:* LISTEN
tcp 0 0 *:59482 *:* LISTEN
udp 0 0 *:35036 *:*
udp 0 0 *:npmp-local *:*
Active UNIX domain sockets (servers and established)
Proto RefCnt Flags Type State I-Node Path
unix 2 [ ACC ] STREAM LISTENING 16972 /tmp/orbit-root/linc-76b-0-6fa08790553d6
unix 2 [ ACC ] STREAM LISTENING 17149 /tmp/orbit-root/linc-794-0-7058d584166d2
unix 2 [ ACC ] STREAM LISTENING 17161 /tmp/orbit-root/linc-792-0-546fe905321cc
unix 2 [ ACC ] STREAM LISTENING 15938 /tmp/orbit-root/linc-74b-0-415135cb6aeab2. 列出 TCP 端口连接
使用 netstat -at 仅列出 TCP（传输控制协议）端口连接。
netstat -at
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 0 *:ssh *:* LISTEN
tcp 0 0 localhost:ipp *:* LISTEN
tcp 0 0 localhost:smtp *:* LISTEN
tcp 0 52 192.168.0.2:ssh 192.168.0.1:egs ESTABLISHED
tcp 1 0 192.168.0.2:59292 www.gov.com:http CLOSE_WAIT3. 列出 UDP 端口连接
使用 netstat -au 仅列出 UDP（用户数据报协议 ）端口连接。
netstat -au
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address Foreign Address State
udp 0 0 *:35036 *:*
udp 0 0 *:npmp-local *:*
udp 0 0 *:mdns *:*4. 列出所有 LISTENING 连接
使用netstat -l列出所有活动侦听端口连接。
netstat -l
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 0 *:sunrpc *:* LISTEN
tcp 0 0 *:58642 *:* LISTEN
tcp 0 0 *:ssh *:* LISTEN
udp 0 0 *:35036 *:*
udp 0 0 *:npmp-local *:*
Active UNIX domain sockets (only servers)
Proto RefCnt Flags Type State I-Node Path
unix 2 [ ACC ] STREAM LISTENING 16972 /tmp/orbit-root/linc-76b-0-6fa08790553d6
unix 2 [ ACC ] STREAM LISTENING 17149 /tmp/orbit-root/linc-794-0-7058d584166d2
unix 2 [ ACC ] STREAM LISTENING 17161 /tmp/orbit-root/linc-792-0-546fe905321cc
unix 2 [ ACC ] STREAM LISTENING 15938 /tmp/orbit-root/linc-74b-0-415135cb6aeab5. 列出所有TCP监听端口
使用选项 netstat -lt 列出所有活动侦听 TCP 端口。
netstat -lt
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 0 *:dctp *:* LISTEN
tcp 0 0 *:mysql *:* LISTEN
tcp 0 0 *:sunrpc *:* LISTEN
tcp 0 0 *:munin *:* LISTEN
tcp 0 0 *:ftp *:* LISTEN
tcp 0 0 localhost.localdomain:ipp *:* LISTEN
tcp 0 0 localhost.localdomain:smtp *:* LISTEN
tcp 0 0 *:http *:* LISTEN
tcp 0 0 *:ssh *:* LISTEN
tcp 0 0 *:https *:* LISTEN6. 列出所有UDP监听端口
使用选项 netstat -lu 列出所有活动侦听 UDP 端口。
netstat -lu
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address State
udp 0 0 *:39578 *:*
udp 0 0 *:meregister *:*
udp 0 0 *:vpps-qua *:*
udp 0 0 *:openvpn *:*
udp 0 0 *:mdns *:*
udp 0 0 *:sunrpc *:*
udp 0 0 *:ipp *:*
udp 0 0 *:60222 *:*
udp 0 0 *:mdns *:*7. 列出所有UNIX监听端口
使用 netstat -lx 列出所有活动的 UNIX 侦听端口。
netstat -lx
Active UNIX domain sockets (only servers)
Proto RefCnt Flags Type State I-Node Path
unix 2 [ ACC ] STREAM LISTENING 4171 @ISCSIADM_ABSTRACT_NAMESPACE
unix 2 [ ACC ] STREAM LISTENING 5767 /var/run/cups/cups.sock
unix 2 [ ACC ] STREAM LISTENING 7082 @/tmp/fam-root-
unix 2 [ ACC ] STREAM LISTENING 6157 /dev/gpmctl
unix 2 [ ACC ] STREAM LISTENING 6215 @/var/run/hald/dbus-IcefTIUkHm
unix 2 [ ACC ] STREAM LISTENING 6038 /tmp/.font-unix/fs7100
unix 2 [ ACC ] STREAM LISTENING 6175 /var/run/avahi-daemon/socket
unix 2 [ ACC ] STREAM LISTENING 4157 @ISCSID_UIP_ABSTRACT_NAMESPACE
unix 2 [ ACC ] STREAM LISTENING 60835836 /var/lib/mysql/mysql.sock
unix 2 [ ACC ] STREAM LISTENING 4645 /var/run/audispd_events
unix 2 [ ACC ] STREAM LISTENING 5136 /var/run/dbus/system_bus_socket
unix 2 [ ACC ] STREAM LISTENING 6216 @/var/run/hald/dbus-wsUBI30V2I
unix 2 [ ACC ] STREAM LISTENING 5517 /var/run/acpid.socket
unix 2 [ ACC ] STREAM LISTENING 5531 /var/run/pcscd.comm8. 按协议显示统计数据
按协议显示统计信息。默认情况下，显示 TCP、UDP、ICMP 和 IP 协议的统计信息。 -s 参数可用于指定一组协议。
netstat -s
Ip:
2461 total packets received
0 forwarded
0 incoming packets discarded
2431 incoming packets delivered
2049 requests sent out
Icmp:
0 ICMP messages received
0 input ICMP message failed.
ICMP input histogram:
1 ICMP messages sent
0 ICMP messages failed
ICMP output histogram:
destination unreachable: 1
Tcp:
159 active connections openings
1 passive connection openings
4 failed connection attempts
0 connection resets received
1 connections established
2191 segments received
1745 segments send out
24 segments retransmited
0 bad segments received.
4 resets sent
Udp:
243 packets received
1 packets to unknown port received.
0 packet receive errors
281 packets sent9. 按 TCP 协议显示统计信息
使用选项netstat -st仅显示TCP协议的统计信息。
netstat -st
Tcp:
2805201 active connections openings
1597466 passive connection openings
1522484 failed connection attempts
37806 connection resets received
1 connections established
57718706 segments received
64280042 segments send out
3135688 segments retransmited
74 bad segments received.
17580 resets sent10. 按UDP协议显示统计数据
netstat -su
Udp:
1774823 packets received
901848 packets to unknown port received.
0 packet receive errors
2968722 packets sent11.显示带有PID的服务名称
显示服务名称及其 PID 编号，使用选项 netstat -tp 将显示“PID/程序名称”。
netstat -tp
Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp 0 0 192.168.0.2:ssh 192.168.0.1:egs ESTABLISHED 2179/sshd
tcp 1 0 192.168.0.2:59292 www.gov.com:http CLOSE_WAIT 1939/clock-applet12. 显示混杂模式
使用 -ac 开关显示混杂模式，netstat 每五秒打印所选信息或刷新屏幕。默认屏幕每秒刷新一次。
netstat -ac 5 | grep tcp
tcp 0 0 *:sunrpc *:* LISTEN
tcp 0 0 *:58642 *:* LISTEN
tcp 0 0 *:ssh *:* LISTEN
tcp 0 0 localhost:ipp *:* LISTEN
tcp 0 0 localhost:smtp *:* LISTEN
tcp 1 0 192.168.0.2:59447 www.gov.com:http CLOSE_WAIT
tcp 0 52 192.168.0.2:ssh 192.168.0.1:egs ESTABLISHED
tcp 0 0 *:sunrpc *:* LISTEN
tcp 0 0 *:ssh *:* LISTEN
tcp 0 0 localhost:ipp *:* LISTEN
tcp 0 0 localhost:smtp *:* LISTEN
tcp 0 0 *:59482 *:* LISTEN13. 显示内核IP路由
使用netstat和route命令显示内核IP路由表。
netstat -r
Kernel IP routing table
Destination Gateway Genmask Flags MSS Window irtt Iface
192.168.0.0 * 255.255.255.0 U 0 0 0 eth0
link-local * 255.255.0.0 U 0 0 0 eth0
default 192.168.0.1 0.0.0.0 UG 0 0 0 eth014. 显示网络接口事务
显示网络接口数据包事务，包括传输和接收具有 MTU 大小的数据包。
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 4459 0 0 0 4057 0 0 0 BMRU
lo 16436 0 8 0 0 0 8 0 0 0 LRU15. 显示内核接口表
显示内核接口表，类似于ifconfig命令。
netstat -ie
Kernel Interface table
eth0 Link encap:Ethernet HWaddr 00:0C:29:B4:DA:21
inet addr:192.168.0.2 Bcast:192.168.0.255 Mask:255.255.255.0
inet6 addr: fe80::20c:29ff:feb4:da21/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:4486 errors:0 dropped:0 overruns:0 frame:0
TX packets:4077 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:2720253 (2.5 MiB) TX bytes:1161745 (1.1 MiB)
Interrupt:18 Base address:0x2000
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:8 errors:0 dropped:0 overruns:0 frame:0
TX packets:8 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:480 (480.0 b) TX bytes:480 (480.0 b)16. 显示 IPv4 和 IPv6 信息
显示 IPv4 和 IPv6 的多播组成员信息。
netstat -g
IPv6/IPv4 Group Memberships
Interface RefCnt Group
--------------- ------ ---------------------
lo 1 all-systems.mcast.net
eth0 1 224.0.0.251
eth0 1 all-systems.mcast.net
lo 1 ff02::1
eth0 1 ff02::202
eth0 1 ff02::1:ffb4:da21
eth0 1 ff02::117、连续打印Netstat信息
要每隔几秒获取一次netstat信息，那么使用下面的命令，它会连续打印netstat信息，比如说每隔几秒。
netstat -c
Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 0 linux-console.net:http sg2nlhg007.shr.prod.s:36944 TIME_WAIT
tcp 0 0 linux-console.net:http sg2nlhg010.shr.prod.s:42110 TIME_WAIT
tcp 0 132 linux-console.net:ssh 115.113.134.3.static-:64662 ESTABLISHED
tcp 0 0 linux-console.net:http crawl-66-249-71-240.g:41166 TIME_WAIT
tcp 0 0 localhost.localdomain:54823 localhost.localdomain:smtp TIME_WAIT
tcp 0 0 localhost.localdomain:54822 localhost.localdomain:smtp TIME_WAIT
tcp 0 0 linux-console.net:http sg2nlhg010.shr.prod.s:42091 TIME_WAIT
tcp 0 0 linux-console.net:http sg2nlhg007.shr.prod.s:36998 TIME_WAIT18. 查找不支持的地址
查找未配置的地址族以及一些有用的信息。
netstat --verbose
netstat: no support for `AF IPX' on this system.
netstat: no support for `AF AX25' on this system.
netstat: no support for `AF X25' on this system.
netstat: no support for `AF NETROM' on this system.19. 寻找听力节目
查看某个端口上运行了多少个监听程序。
netstat -ap | grep http
tcp 0 0 *:http *:* LISTEN 9056/httpd
tcp 0 0 *:https *:* LISTEN 9056/httpd
tcp 0 0 linux-console.net:http sg2nlhg008.shr.prod.s:35248 TIME_WAIT -
tcp 0 0 linux-console.net:http sg2nlhg007.shr.prod.s:57783 TIME_WAIT -
tcp 0 0 linux-console.net:http sg2nlhg007.shr.prod.s:57769 TIME_WAIT -
tcp 0 0 linux-console.net:http sg2nlhg008.shr.prod.s:35270 TIME_WAIT -
tcp 0 0 linux-console.net:http sg2nlhg009.shr.prod.s:41637 TIME_WAIT -
tcp 0 0 linux-console.net:http sg2nlhg009.shr.prod.s:41614 TIME_WAIT -
unix 2 [ ] STREAM CONNECTED 88586726 10394/httpd20. 显示原始网络统计信息
netstat --statistics --raw
Ip:
62175683 total packets received
52970 with invalid addresses
0 forwarded
Icmp:
875519 ICMP messages received
destination unreachable: 901671
echo request: 8
echo replies: 16253
IcmpMsg:
InType0: 83
IpExt:
InMcastPkts: 117就是这样，如果您正在寻找有关 netstat 命令的更多信息和选项，请参阅 netstat 手册文档或使用 man netstat 命令来了解所有信息。
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