Linux上的网络相关的那些命令—netstat命令、ip添加删除命令、ss命令、对网卡设置别名

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netstat命令

显示网络连接：

netstat [--tcp|-t] [--udp|-u] [--raw|-w] [--listening|-l] [--all|-a] [--numeric|-n] [--extend|-e[--extend|-e]] [--program|-p]

选项	代表含义
-t	tcp协议相关
-u	udp协议相关
-w	raw socket相关
-l	处于监听状态
-a	所有状态
-n	以数字显示IP和端口；
-e	扩展格式
-p	显示相关进程及PID

常用组合：
-ant, -anu, -tnl, -unl

示例：

[root@centos ~]# netstat -ant
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address           Foreign Address         State      
tcp        0      0 127.0.0.1:631           0.0.0.0:*               LISTEN     
tcp        0      0 127.0.0.1:25            0.0.0.0:*               LISTEN     
tcp        0      0 0.0.0.0:111             0.0.0.0:*               LISTEN     
tcp        0      0 192.168.122.1:53        0.0.0.0:*               LISTEN     
tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN     
tcp        0     52 192.168.44.140:22       192.168.44.1:59598      ESTABLISHED
tcp6       0      0 ::1:631                 :::*                    LISTEN     
tcp6       0      0 ::1:25                  :::*                    LISTEN     
tcp6       0      0 :::111                  :::*                    LISTEN     
tcp6       0      0 :::22                   :::*                    LISTEN     
[root@centos ~]# netstat -anu
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address           Foreign Address         State      
udp        0      0 0.0.0.0:961             0.0.0.0:*                          
udp        0      0 0.0.0.0:59443           0.0.0.0:*                          
udp        0      0 192.168.122.1:53        0.0.0.0:*                          
udp        0      0 0.0.0.0:67              0.0.0.0:*                          
udp        0      0 0.0.0.0:68              0.0.0.0:*                          
udp        0      0 0.0.0.0:111             0.0.0.0:*                          
udp        0      0 0.0.0.0:5353            0.0.0.0:*                          
udp        0      0 127.0.0.1:323           0.0.0.0:*                          
udp6       0      0 :::961                  :::*                               
udp6       0      0 :::111                  :::*                               
udp6       0      0 ::1:323                 :::*                               
[root@centos ~]# netstat -tnl
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State      
tcp        0      0 127.0.0.1:631           0.0.0.0:*               LISTEN     
tcp        0      0 127.0.0.1:25            0.0.0.0:*               LISTEN     
tcp        0      0 0.0.0.0:111             0.0.0.0:*               LISTEN     
tcp        0      0 192.168.122.1:53        0.0.0.0:*               LISTEN     
tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN     
tcp6       0      0 ::1:631                 :::*                    LISTEN     
tcp6       0      0 ::1:25                  :::*                    LISTEN     
tcp6       0      0 :::111                  :::*                    LISTEN     
tcp6       0      0 :::22                   :::*                    LISTEN     
[root@centos ~]# netstat -unl
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State      
udp        0      0 0.0.0.0:961             0.0.0.0:*                          
udp        0      0 0.0.0.0:59443           0.0.0.0:*                          
udp        0      0 192.168.122.1:53        0.0.0.0:*                          
udp        0      0 0.0.0.0:67              0.0.0.0:*                          
udp        0      0 0.0.0.0:68              0.0.0.0:*                          
udp        0      0 0.0.0.0:111             0.0.0.0:*                          
udp        0      0 0.0.0.0:5353            0.0.0.0:*                          
udp        0      0 127.0.0.1:323           0.0.0.0:*                          
udp6       0      0 :::961                  :::*                               
udp6       0      0 :::111                  :::*                               
udp6       0      0 ::1:323                 :::*                               

显示路由表：

netstat {
     --route|-r}  [--numeric|-n]

-r: 显示内核路由表
-n: 数字格式

示例：

[root@centos ~]# netstat -rn
Kernel IP routing table  ##内核ip路由表
Destination     Gateway         Genmask         Flags   MSS Window  irtt Iface
0.0.0.0         192.168.44.2    0.0.0.0         UG        0 0          0 eno16777736
192.168.10.0    0.0.0.0         255.255.255.0   U         0 0          0 eth1
192.168.20.0    0.0.0.0         255.255.255.0   U         0 0          0 eth1
192.168.44.0    0.0.0.0         255.255.255.0   U         0 0          0 eno16777736
192.168.122.0   0.0.0.0         255.255.255.0   U         0 0          0 virbr0

显示接口统计数据：

netstat {
     --interfaces|-I|-i} [iface] [--all|-a] [--extend|-e] [--program|-p] [--numeric|-n]

netstat -i
ifconfig -s eth1

示例：

[root@centos ~]# ifconfig -s eth1
Iface      MTU    RX-OK RX-ERR RX-DRP RX-OVR    TX-OK TX-ERR TX-DRP TX-OVR Flg
eth1             1500        0      0      0 0            25      0      0      0 BMRU
[root@centos ~]# netstat -i
Kernel Interface table
Iface             MTU    RX-OK RX-ERR RX-DRP RX-OVR    TX-OK TX-ERR TX-DRP TX-OVR Flg
eno16777736      1500     3526      0      0 0          1160      0      0      0 BMRU
eth1             1500        0      0      0 0            25      0      0      0 BMRU
eth1:1           1500      - no statistics available -                        BMRU
eth2             1500        0      0      0 0          1780      0      0      0 BMRU
lo              65536       40      0      0 0            40      0      0      0 LRU
virbr0           1500        0      0      0 0             0      0      0      0 BMU
[root@centos ~]# ifconfig -s eth1
Iface      MTU    RX-OK RX-ERR RX-DRP RX-OVR    TX-OK TX-ERR TX-DRP TX-OVR Flg
eth1             1500        0      0      0 0            25      0      0      0 BMRU
[root@centos ~]# ifconfig -s eth2
Iface      MTU    RX-OK RX-ERR RX-DRP RX-OVR    TX-OK TX-ERR TX-DRP TX-OVR Flg
eth2             1500        0      0      0 0          1780      0      0      0 BMRU

ip命令

配置Linux网络属性：ip命令
ip[ OPTIONS ] OBJECT { COMMAND | help }
OBJECT = { link | addr| route }
可设置属性：

up and down：激活或禁用指定接口————使用命令：ifup/ifdown
show[dev IFACE]：指定接口
[up]：仅显示处于激活状态的接口

示例：

[root@centos ~]# ip addr show
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: eno16777736: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:0c:29:37:9b:96 brd ff:ff:ff:ff:ff:ff
    inet 192.168.44.140/24 brd 192.168.44.255 scope global noprefixroute eno16777736
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fe37:9b96/64 scope link 
       valid_lft forever preferred_lft forever
3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:0c:29:37:9b:a0 brd ff:ff:ff:ff:ff:ff
    inet 192.168.10.3/24 brd 192.168.10.255 scope global noprefixroute eth1
       valid_lft forever preferred_lft forever
    inet 192.168.20.2/24 brd 192.168.20.255 scope global noprefixroute eth1:1
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fe37:9ba0/64 scope link 
       valid_lft forever preferred_lft forever
4: eth2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:0c:29:37:9b:aa brd ff:ff:ff:ff:ff:ff
5: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN qlen 1000
    link/ether 52:54:00:34:38:6d brd ff:ff:ff:ff:ff:ff
    inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0
       valid_lft forever preferred_lft forever
6: virbr0-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast master virbr0 state DOWN qlen 1000
    link/ether 52:54:00:34:38:6d brd ff:ff:ff:ff:ff:ff
[root@centos ~]# ip addr show dev eth1
3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:0c:29:37:9b:a0 brd ff:ff:ff:ff:ff:ff
    inet 192.168.10.3/24 brd 192.168.10.255 scope global noprefixroute eth1
       valid_lft forever preferred_lft forever
    inet 192.168.20.2/24 brd 192.168.20.255 scope global noprefixroute eth1:1
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fe37:9ba0/64 scope link 
       valid_lft forever preferred_lft forever


[root@centos ~]# ip route show
default via 192.168.44.2 dev eno16777736  proto static  metric 100 
192.168.10.0/24 dev eth1  proto kernel  scope link  src 192.168.10.3  metric 101 
192.168.20.0/24 dev eth1  proto kernel  scope link  src 192.168.20.2  metric 101 
192.168.44.0/24 dev eno16777736  proto kernel  scope link  src 192.168.44.140  metric 100 
192.168.122.0/24 dev virbr0  proto kernel  scope link  src 192.168.122.1 
[root@centos ~]# ip route show dev eth1
192.168.10.0/24  proto kernel  scope link  src 192.168.10.3  metric 101 
192.168.20.0/24  proto kernel  scope link  src 192.168.20.2  metric 101 

ip添加命令

ip addr {
      add | del } IFADDR dev STRING

[label LABEL]：添加地址时指明网卡别名
[scope {global|link|host}]：指明作用域
global: 全局可用
link: 仅链接可用
host: 本机可用
[broadcast ADDRESS]：指明广播地址
ip address show -look at protocol addresses
[dev DEVICE]
[label PATTERN]
[primary and secondary]

示例：

[root@centos ~]# route
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
default         192.168.44.2    0.0.0.0         UG    100    0        0 eno16777736
192.168.10.0    0.0.0.0         255.255.255.0   U     101    0        0 eth1
192.168.20.0    0.0.0.0         255.255.255.0   U     101    0        0 eth1
192.168.44.0    0.0.0.0         255.255.255.0   U     100    0        0 eno16777736
192.168.122.0   0.0.0.0         255.255.255.0   U     0      0        0 virbr0
[root@centos ~]# ip addr add 192.168.33.130/24 dev eno16777736
[root@centos ~]# route
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
default         192.168.44.2    0.0.0.0         UG    100    0        0 eno16777736
192.168.10.0    0.0.0.0         255.255.255.0   U     101    0        0 eth1
192.168.20.0    0.0.0.0         255.255.255.0   U     101    0        0 eth1
192.168.33.0    0.0.0.0         255.255.255.0   U     0      0        0 eno16777736
192.168.44.0    0.0.0.0         255.255.255.0   U     100    0        0 eno16777736
192.168.122.0   0.0.0.0         255.255.255.0   U     0      0        0 virbr0
[root@centos ~]# ip addr del 192.168.33.130/24 dev eno16777736
[root@centos ~]# route
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
default         192.168.44.2    0.0.0.0         UG    100    0        0 eno16777736
192.168.10.0    0.0.0.0         255.255.255.0   U     101    0        0 eth1
192.168.20.0    0.0.0.0         255.255.255.0   U     101    0        0 eth1
192.168.44.0    0.0.0.0         255.255.255.0   U     100    0        0 eno16777736
192.168.122.0   0.0.0.0         255.255.255.0   U     0      0        0 virbr0

ip添加路由

添加路由：ip route add
ip route add TARGET via GW dev IFACE srcSOURCE_IP
TARGET:
主机路由：IP
网络路由：NETWORK/MASK
ip route add 192.168.0.0/24 via 172.16.0.1
ip route add 192.168.1.13 via 172.16.0.1
添加网关：ip route add default via GW dev IFACE
ip route add default via 172.16.0.1
删除路由：ip route delete
ip route del TARGET
显示路由：ip route show|list
清空路由表：ip route flush[dev IFACE] [via PREFIX]

示例：

[root@centos ~]# ip route show
default via 192.168.44.2 dev eno16777736  proto static  metric 100 
192.168.10.0/24 dev eth1  proto kernel  scope link  src 192.168.10.3  metric 101 
192.168.20.0/24 dev eth1  proto kernel  scope link  src 192.168.20.2  metric 101 
192.168.44.0/24 dev eno16777736  proto kernel  scope link  src 192.168.44.140  metric 100 
192.168.122.0/24 dev virbr0  proto kernel  scope link  src 192.168.122.1 
[root@centos ~]# ip route add 192.168.33.0/24 via 192.168.44.2
[root@centos ~]# ip route show
default via 192.168.44.2 dev eno16777736  proto static  metric 100 
192.168.10.0/24 dev eth1  proto kernel  scope link  src 192.168.10.3  metric 101 
192.168.20.0/24 dev eth1  proto kernel  scope link  src 192.168.20.2  metric 101 
192.168.33.0/24 via 192.168.44.2 dev eno16777736 
192.168.44.0/24 dev eno16777736  proto kernel  scope link  src 192.168.44.140  metric 100 
192.168.122.0/24 dev virbr0  proto kernel  scope link  src 192.168.122.1 
[root@centos ~]# ip route del 192.168.33.0/24 via 192.168.44.2
[root@centos ~]# ip route show
default via 192.168.44.2 dev eno16777736  proto static  metric 100 
192.168.10.0/24 dev eth1  proto kernel  scope link  src 192.168.10.3  metric 101 
192.168.20.0/24 dev eth1  proto kernel  scope link  src 192.168.20.2  metric 101 
192.168.44.0/24 dev eno16777736  proto kernel  scope link  src 192.168.44.140  metric 100 
192.168.122.0/24 dev virbr0  proto kernel  scope link  src 192.168.122.1 

ss命令

格式：ss [OPTION]… [FILTER]
ss命令的使用同netstat命令大致相同，但是过程不同：
netstat通过遍历proc来获取socket信息，ss使用netlink与内核tcp_diag模块通信获取socket信息。

选项	代表含义
-t	tcp协议相关
-u	udp协议相关
-w	裸套接字相关
-x	unixsock相关
-l	listen状态的连接
-a	所有
-n	数字格式
-p	相关的程序及PID
-e	扩展的信息
-m	内存用量
-o	计时器信息

示例：

[root@centos ~]# ss -ant
State       Recv-Q Send-Q Local Address:Port               Peer Address:Port              
LISTEN      0      128     127.0.0.1:631                         *:*                  
LISTEN      0      100     127.0.0.1:25                          *:*                  
LISTEN      0      128             *:111                         *:*                  
LISTEN      0      5      192.168.122.1:53                          *:*                  
LISTEN      0      128             *:22                          *:*                  
ESTAB       0      0      192.168.44.140:22                 192.168.44.1:59598              
LISTEN      0      128           ::1:631                        :::*                  
LISTEN      0      100           ::1:25                         :::*                  
LISTEN      0      128            :::111                        :::*                  
LISTEN      0      128            :::22                         :::*                  
[root@centos ~]# ss -anu
State       Recv-Q Send-Q Local Address:Port               Peer Address:Port              
UNCONN      0      0               *:961                         *:*                  
UNCONN      0      0               *:59443                       *:*                  
UNCONN      0      0      192.168.122.1:53                          *:*                  
UNCONN      0      0        *%virbr0:67                          *:*                  
UNCONN      0      0               *:111                         *:*                  
UNCONN      0      0               *:5353                        *:*                  
UNCONN      0      0       127.0.0.1:323                         *:*                  
UNCONN      0      0              :::961                        :::*                  
UNCONN      0      0              :::111                        :::*                  
UNCONN      0      0             ::1:323                        :::*                            

TCP的常见状态：
tcpfinite state machine:
LISTEN: 监听
ESTABLISHED：已建立的连接
FIN_WAIT_1
FIN_WAIT_2
SYN_SENT
SYN_RECV
CLOSED
ss -l 显示本地打开的所有端口
ss -pl 显示每个进程具体打开的socket
ss -t -a 显示所有tcp socket
ss -u -a 显示所有的UDP Socekt
ss -o state established ‘( dport = :ssh or sport = :ssh )’ 显示所有已建立的ssh连接
ss -o state established ‘( dport = :http or sport = :http )’ 显示所有已建立的HTTP连接
ss -s 列出当前socket详细信息

示例：

[root@centos ~]# ss -ant state ESTABLISHED
Recv-Q Send-Q   Local Address:Port                  Peer Address:Port              
0      52      192.168.44.140:22                    192.168.44.1:59598
[root@centos ~]# ss -ant state ESTABLISHED
Recv-Q Send-Q   Local Address:Port                  Peer Address:Port              
0      52      192.168.44.140:22                    192.168.44.1:59598              
[root@centos ~]# ss -s
Total: 659 (kernel 1530)
TCP:   11 (estab 1, closed 1, orphaned 0, synrecv 0, timewait 0/0), ports 0

Transport Total     IP        IPv6
*	  1530      -         -        
RAW	  1         0         1        
UDP	  11        8         3        
TCP	  10        6         4        
INET	  22        14        8        
FRAG	  0         0         0        

网络配置文件

IP、MASK、GW、DNS相关配置文件：/etc/sysconfig/network-scripts/ifcfg-IFACE

配置文件中的参数：

参数	含义
ONBOOT	在系统引导时是否激活此设备
TYPE	接口类型；常见有的Ethernet, Bridge
UUID	设备的惟一标识
IPADDR	指明IP地址
NETMASK	子网掩码
GATEWAY	默认网关
DNS1	第一个DNS服务器指向
DNS2	第二个DNS服务器指向
USERCTL	普通用户是否可控制此设备
PEERDNS	如果BOOTPROTO的值为“dhcp”，是否允许dhcp server分配的dns服务器指向信息直接覆盖至/etc/resolv.conf文件中

配置文件有两种风格
(1) TARGET via GW
如：10.0.0.0/8 via 172.16.0.1
(2) 每三行定义一条路由
ADDRESS#=TARGET
NETMASK#=mask
GATEWAY#=GW

网卡别名

对虚拟主机有用
将多个IP地址绑定到一个NIC上
eth0:1 、eth0:2、eth0:3
有两种方式：
一、

ifconfig命令:
ifconfig eth0:0 192.168.1.100/24 up
ifconfig eth0:0 down
ip命令：
ip addr add 172.16.1.2/24 dev eth0 label eth0:0
ip addr add 172.16.1.1/24 dev eth0 label eth0:0
ip addr del 172.16.1.2/24 dev eth0 label eth0:0
ip addr del 172.16.1.1/24 dev eth0 label eth0:0

二、
使用配置文件
为每个设备别名生成独立的接口配置文件
配置文件命名为ifcfg-ethX:xxx
必须使用静态联网
配置文件内容例如：

NAME=eth0:0
DEVICE=eth0:0
IPADDR=10.10.10.10
NETMASK=255.0.0.0
ONPARENT=yes

注意：service network restart 生效（重启网络服务）

示例：

vim /etc/sysconfig/network-scripts/ifcfg-eth1:1

  1 TYPE="Ethernet"
  2 BOOTPROTO="static"
  3 DEFROUTE="yes"
  4 PEERDNS="yes"
  5 PEERROUTES="yes"
  6 NAME="eth1:1"
  7 IPADDR=192.168.33.3
  8 NETMASK=255.255.255.0
  9 DEVICE=eth1:1                                                                      
 10 ONBOOT="yes"


[root@centos network-scripts]# ifconfig
eno16777736: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.44.140  netmask 255.255.255.0  broadcast 192.168.44.255
        inet6 fe80::20c:29ff:fe37:9b96  prefixlen 64  scopeid 0x20<link>
        ether 00:0c:29:37:9b:96  txqueuelen 1000  (Ethernet)
        RX packets 3769  bytes 318454 (310.9 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 2304  bytes 393293 (384.0 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

eth1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.10.3  netmask 255.255.255.0  broadcast 192.168.10.255
        inet6 fe80::20c:29ff:fe37:9ba0  prefixlen 64  scopeid 0x20<link>
        ether 00:0c:29:37:9b:a0  txqueuelen 1000  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 180  bytes 26930 (26.2 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

eth1:1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.33.3  netmask 255.255.255.0  broadcast 192.168.33.255
        ether 00:0c:29:37:9b:a0  txqueuelen 1000  (Ethernet)

lo: 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 1000  (Local Loopback)
        RX packets 45  bytes 3560 (3.4 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 45  bytes 3560 (3.4 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

virbr0: flags=4099<UP,BROADCAST,MULTICAST>  mtu 1500
        inet 192.168.122.1  netmask 255.255.255.0  broadcast 192.168.122.255
        ether 52:54:00:34:38:6d  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