运行netstat，查看激活Internet连接。具体参数列表请查看帮助文件。dell@dell:~$ man netstatdell@dell:~$ info netstatnetstat命令可以显
运行netstat，查看激活Internet连接。具体参数列表请查看帮助文件。
dell@dell:~$ man netstatdell@dell:~$ info netstatnetstat命令可以显示网络连接，路由表，接口状态，伪装连接，网络链路信息和组播成员组。
dell@dell:~$ netstat -ano | more激活Internet连接 (服务器和已建立连接的)Proto Recv-Q Send-Q Local Address Foreign Address State Timertcp 0 0 0.0.0.0:80 0.0.0.0:* LISTEN 关闭 (0.00/0/0)tcp 0 0 127.0.1.1:53 0.0.0.0:* LISTEN 关闭 (0.00/0/0)tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 关闭 (0.00/0/0)tcp 0 36 172.20.0.253:22 172.20.0.133:6576 ESTABLISHED 打开 (0.35/0/0)tcp6 0 0 :::8080 :::* LISTEN 关闭 (0.00/0/0)tcp6 0 0 :::22 :::* LISTEN 关闭 (0.00/0/0)udp 0 0 0.0.0.0:5353 0.0.0.0:* 关闭 (0.00/0/0)udp 0 0 0.0.0.0:36171 0.0.0.0:* 关闭 (0.00/0/0)udp 0 0 0.0.0.0:58934 0.0.0.0:* 关闭 (0.00/0/0)udp 0 0 127.0.1.1:53 0.0.0.0:* 关闭 (0.00/0/0)udp 0 0 0.0.0.0:68 0.0.0.0:* 关闭 (0.00/0/0)udp 0 0 0.0.0.0:631 0.0.0.0:* 关闭 (0.00/0/0)udp6 0 0 :::5353 :::* 关闭 (0.00/0/0)udp6 0 0 :::46962 :::* 关闭 (0.00/0/0)raw6 0 0 :::58 :::* 7 关闭 (0.00/0/0)活跃的UNIX域套接字 (服务器和已建立连接的)Proto RefCnt Flags Type State I-Node 路径unix 2 [ ACC ] 流 LISTENING 37601 @/tmp/dbus-a4YY6cvUmDunix 2 [ ] 数据报 43222 /run/user/108/systemd/notifyunix 2 [ ACC ] 流 LISTENING 37563 @/tmp/ibus/dbus-JHsXop1sunix 2 [ ] 数据报 20851 /run/user/1000/systemd/notifyunix 2 [ ACC ] 流 LISTENING 43227 /run/user/108/systemd/privateunix 2 [ ACC ] 流 LISTENING 20852 /run/user/1000/systemd/privateunix 2 [ ACC ] SEQPACKET LISTENING 1809 /run/udev/control--更多--也可以运行netstat -nutlp，t和u分别表示TCP与UDP连接。
[root@localhost ~]# netstat -nutlpActive Internet connections (only servers)Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program nametcp 0 0 0.0.0.0:3306 0.0.0.0:* LISTEN 4452/mysqldtcp 0 0 0.0.0.0:111 0.0.0.0:* LISTEN 1/systemdtcp 0 0 192.168.122.1:53 0.0.0.0:* LISTEN 2517/dnsmasqtcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 1245/sshdtcp 0 0 127.0.0.1:631 0.0.0.0:* LISTEN 1226/cupsdtcp 0 0 127.0.0.1:25 0.0.0.0:* LISTEN 2485/mastertcp 0 0 0.0.0.0:10050 0.0.0.0:* LISTEN 9053/zabbix_agentdtcp6 0 0 :::111 :::* LISTEN 1/systemdtcp6 0 0 :::80 :::* LISTEN 1651/httpdtcp6 0 0 :::22 :::* LISTEN 1245/sshdtcp6 0 0 ::1:631 :::* LISTEN 1226/cupsdtcp6 0 0 ::1:25 :::* LISTEN 2485/mastertcp6 0 0 :::443 :::* LISTEN 1651/httpdtcp6 0 0 :::10050 :::* LISTEN 9053/zabbix_agentdudp 0 0 127.0.0.1:323 0.0.0.0:* 842/chronydudp 0 0 0.0.0.0:40060 0.0.0.0:* 807/avahi-daemon: rudp 0 0 0.0.0.0:5353 0.0.0.0:* 807/avahi-daemon: rudp 0 0 192.168.122.1:53 0.0.0.0:* 2517/dnsmasqudp 0 0 0.0.0.0:67 0.0.0.0:* 2517/dnsmasqudp6 0 0 ::1:323 :::* 842/chronyd[root@localhost ~]#还有一种方法是运行 lsof -i。CentOS 7需要安装。
[root@promote ~]# yum install lsof -y安装完成执行命令如下所示：
[root@localhost ~]# lsof -iCOMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAMEsystemd 1 root 45u IPv6 15960 0t0 TCP *:sunrpc (LISTEN)systemd 1 root 46u IPv4 15961 0t0 TCP *:sunrpc (LISTEN)avahi-dae 807 avahi 12u IPv4 18053 0t0 UDP *:mdnsavahi-dae 807 avahi 13u IPv4 18863 0t0 UDP *:40060chronyd 842 chrony 1u IPv4 17867 0t0 UDP localhost:323chronyd 842 chrony 2u IPv6 17868 0t0 UDP localhost:323chronyd 842 chrony 4u IPv4 1272721 0t0 UDP localhost.localdomain:53081->61-216-153-107.HINET-IP.hinet.net:ntpcupsd 1226 root 11u IPv6 23760 0t0 TCP localhost:ipp (LISTEN)cupsd 1226 root 12u IPv4 23761 0t0 TCP localhost:ipp (LISTEN)sshd 1245 root 3u IPv4 22054 0t0 TCP *:ssh (LISTEN)sshd 1245 root 4u IPv6 22056 0t0 TCP *:ssh (LISTEN)httpd 1651 apache 4u IPv6 32672 0t0 TCP *:http (LISTEN)httpd 1651 apache 6u IPv6 32680 0t0 TCP *:https (LISTEN)httpd 1653 apache 4u IPv6 32672 0t0 TCP *:http (LISTEN)httpd 1653 apache 6u IPv6 32680 0t0 TCP *:https (LISTEN)httpd 1654 apache 4u IPv6 32672 0t0 TCP *:http (LISTEN)httpd 1654 apache 6u IPv6 32680 0t0 TCP *:https (LISTEN)httpd 1655 apache 4u IPv6 32672 0t0 TCP *:http (LISTEN)httpd 1655 apache 6u IPv6 32680 0t0 TCP *:https (LISTEN)httpd 1656 apache 4u IPv6 32672 0t0 TCP *:http (LISTEN)httpd 1656 apache 6u IPv6 32680 0t0 TCP *:https (LISTEN)httpd 1657 apache 4u IPv6 32672 0t0 TCP *:http (LISTEN)httpd 1657 apache 6u IPv6 32680 0t0 TCP *:https (LISTEN)master 2485 root 13u IPv4 24672 0t0 TCP localhost:smtp (LISTEN)master 2485 root 14u IPv6 24673 0t0 TCP localhost:smtp (LISTEN)dnsmasq 2517 nobody 3u IPv4 23996 0t0 UDP *:bootpsdnsmasq 2517 nobody 5u IPv4 24003 0t0 UDP localhost.localdomain:domaindnsmasq 2517 nobody 6u IPv4 24004 0t0 TCP localhost.localdomain:domain (LISTEN)sshd 2605 root 3u IPv4 1272258 0t0 TCP localhost.localdomain:ssh->172.20.0.133:6562 (ESTABLISHED)httpd 2726 apache 4u IPv6 32672 0t0 TCP *:http (LISTEN)httpd 2726 apache 6u IPv6 32680 0t0 TCP *:https (LISTEN)httpd 2728 apache 4u IPv6 32672 0t0 TCP *:http (LISTEN)httpd 2728 apache 6u IPv6 32680 0t0 TCP *:https (LISTEN)httpd 4200 root 4u IPv6 32672 0t0 TCP *:http (LISTEN)httpd 4200 root 6u IPv6 32680 0t0 TCP *:https (LISTEN)mysqld 4452 mysql 14u IPv4 34998 0t0 TCP *:mysql (LISTEN)zabbix_ag 9053 zabbix 4u IPv4 56573 0t0 TCP *:zabbix-agent (LISTEN)zabbix_ag 9053 zabbix 5u IPv6 56574 0t0 TCP *:zabbix-agent (LISTEN)zabbix_ag 9054 zabbix 4u IPv4 56573 0t0 TCP *:zabbix-agent (LISTEN)zabbix_ag 9054 zabbix 5u IPv6 56574 0t0 TCP *:zabbix-agent (LISTEN)zabbix_ag 9055 zabbix 4u IPv4 56573 0t0 TCP *:zabbix-agent (LISTEN)zabbix_ag 9055 zabbix 5u IPv6 56574 0t0 TCP *:zabbix-agent (LISTEN)zabbix_ag 9056 zabbix 4u IPv4 56573 0t0 TCP *:zabbix-agent (LISTEN)zabbix_ag 9056 zabbix 5u IPv6 56574 0t0 TCP *:zabbix-agent (LISTEN)zabbix_ag 9057 zabbix 4u IPv4 56573 0t0 TCP *:zabbix-agent (LISTEN)zabbix_ag 9057 zabbix 5u IPv6 56574 0t0 TCP *:zabbix-agent (LISTEN)zabbix_ag 9058 zabbix 4u IPv4 56573 0t0 TCP *:zabbix-agent (LISTEN)zabbix_ag 9058 zabbix 5u IPv6 56574 0t0 TCP *:zabbix-agent (LISTEN)[root@localhost ~]##查看80端口[root@localhost ~]# lsof -i tcp:80COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAMEhttpd 1651 apache 4u IPv6 32672 0t0 TCP *:http (LISTEN)httpd 1653 apache 4u IPv6 32672 0t0 TCP *:http (LISTEN)httpd 1654 apache 4u IPv6 32672 0t0 TCP *:http (LISTEN)httpd 1655 apache 4u IPv6 32672 0t0 TCP *:http (LISTEN)httpd 1656 apache 4u IPv6 32672 0t0 TCP *:http (LISTEN)httpd 1657 apache 4u IPv6 32672 0t0 TCP *:http (LISTEN)httpd 2726 apache 4u IPv6 32672 0t0 TCP *:http (LISTEN)httpd 2728 apache 4u IPv6 32672 0t0 TCP *:http (LISTEN)httpd 4200 root 4u IPv6 32672 0t0 TCP *:http (LISTEN)[root@localhost ~]#lsof -i :port命令，port（端口号）是在0-65535范围内整数。
不过需要指出，外部主机访问对应端口可能还需要防火墙开启对应端口，本文不再详述。
下文补充一些常见其他netstat用法。
查看用户进程PID和进程名称（需要root权限）。
dell@dell:~$ netstat -nlutp（并非所有进程都能被检测到，所有非本用户的进程信息将不会显示，如果想看到所有信息，则必须切换到 root 用户）激活Internet连接 (仅服务器)Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program nametcp 0 0 0.0.0.0:80 0.0.0.0:* LISTEN -tcp 0 0 127.0.1.1:53 0.0.0.0:* LISTEN -tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN -tcp6 0 0 :::8080 :::* LISTEN -tcp6 0 0 :::22 :::* LISTEN -udp 0 0 0.0.0.0:5353 0.0.0.0:* -udp 0 0 0.0.0.0:36171 0.0.0.0:* -udp 0 0 0.0.0.0:58934 0.0.0.0:* -udp 0 0 127.0.1.1:53 0.0.0.0:* -udp 0 0 0.0.0.0:68 0.0.0.0:* -udp 0 0 0.0.0.0:631 0.0.0.0:* -udp6 0 0 :::5353 :::* -udp6 0 0 :::46962 :::* -#查看用户进程PID、进程名称和用户名#（并非所有进程都能被检测到，所有非本用户的进程信息将不会显示，如果想看到所有信息，则必须切换到 root 用户）root@minmin-VirtualBox:~# netstat -nelutp | more激活Internet连接 (仅服务器)Proto Recv-Q Send-Q Local Address Foreign Address State User Inode PID/Program nametcp 0 0 127.0.1.1:53 0.0.0.0:* LISTEN 0 19407 890/dnsmasqtcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 0 20296 856/sshdtcp 0 0 127.0.0.1:631 0.0.0.0:* LISTEN 0 26054 1994/cupsdtcp 0 0 127.0.0.1:5432 0.0.0.0:* LISTEN 122 19426 878/postgrestcp6 0 0 :::22 :::* LISTEN 0 20301 856/sshdtcp6 0 0 ::1:631 :::* LISTEN 0 26053 1994/cupsdudp 0 0 0.0.0.0:50035 0.0.0.0:* 110 18396 711/avahi-daemon: rudp 0 0 0.0.0.0:37873 0.0.0.0:* 65534 19609 890/dnsmasqudp 0 0 127.0.1.1:53 0.0.0.0:* 0 19406 890/dnsmasqudp 0 0 0.0.0.0:68 0.0.0.0:* 0 19326 873/dhclientudp 0 0 0.0.0.0:631 0.0.0.0:* 0 26069 1995/cups-browsedudp 0 0 0.0.0.0:5353 0.0.0.0:* 110 18394 711/avahi-daemon: rudp6 0 0 :::37979 :::* 110 18397 711/avahi-daemon: rudp6 0 0 :::5353 :::* 110 18395 711/avahi-daemon: rroot@minmin-VirtualBox:~#查看本地路由表。
dell@dell:~$ netstat -r内核 IP 路由表Destination Gateway Genmask Flags MSS Window irtt Ifacedefault 172.20.0.1 0.0.0.0 UG 0 0 0 enp2s0172.20.0.0 * 255.255.255.0 U 0 0 0 enp2s0dell@dell:~$查看网卡信息。
#显示本地网卡信息[root@localhost ~]# netstat -iKernel Interface tableIface MTU RX-OK RX-ERR RX-DRP RX-OVR TX-OK TX-ERR TX-DRP TX-OVR Flglo 65536 84348 0 0 0 84348 0 0 0 LRUp1p1 1500 1358482 0 0 0 407522 0 0 0 BMRUvirbr0 1500 0 0 0 0 0 0 0 0 BMU#显示本地网卡详细信息，对比ifconfig[root@localhost ~]# netstat -ieKernel Interface tablelo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536 inet 127.0.0.1 netmask 255.0.0.0 inet6 ::1 prefixlen 128 scopeid 0x10<host> loop txqueuelen 1 (Local Loopback) RX packets 84348 bytes 259268763 (247.2 MiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 84348 bytes 259268763 (247.2 MiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0p1p1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet 172.20.0.155 netmask 255.255.255.0 broadcast 172.20.0.255 inet6 fe80::ffac:ac35:db67:e8a5 prefixlen 64 scopeid 0x20<link> ether c8:1f:66:1c:51:3c txqueuelen 1000 (Ethernet) RX packets 1358498 bytes 928997502 (885.9 MiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 407531 bytes 59529226 (56.7 MiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0virbr0: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500 inet 192.168.122.1 netmask 255.255.255.0 broadcast 192.168.122.255 ether 52:54:00:2a:09:b3 txqueuelen 1000 (Ethernet) RX packets 0 bytes 0 (0.0 B) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 0 bytes 0 (0.0 B) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0[root@localhost ~]#netstat -s可以统计各个协议数据信息，-c可以固定时间刷新统计信息。
CentOS 7 默认没有安装net-tools软件包，可以使用命令 ip addr查看网络信息。
