一：Linux的網絡屬性配置：
(1)網絡分層的作用
物理層：用於界定網絡設備接口標準，電器特性等硬件標準
數據鏈路層：識別網絡設備，數據校驗，幀的開始和結束
網絡層：IP通訊最佳路徑選擇
傳輸層：三次握手，流量控制，丟包重傳，傳輸協議TCP/UDP
會話層：客戶端與服務端建立會話
表示層：數據傳輸的加密、壓縮、編碼等
應用層：計算機通訊之間的應用
(2)Linux主機接入網絡的方式
IP/NETMASK:實現本地網絡通信
路由(網關)：可以進行跨網絡通信
DNS服務器：基於主機名的通信，linux可以最多有三個DNS地址
(3)DNS服務器配置文件：/etc/resolv.conf
配置格式：
nameserver 114.114.114.114
二：使用命令配置彙總
(1)ifcfg家族
ifocnfig: 配置IP，NETMASK
route:路由
netstat：狀態機統計數據查看
(2)iproute家族
ip OBJECT
addr：地址和掩碼
link：接口
route：路由
ss：狀態及統計數據查看
(3)CentOS 7：nm 家族
nmcli：命令行工具
nmtui：text window工具
三、ifcfg家族配置管理
(1)ifconfig命令:配置網絡接口
ifconfig [-a] [interface]
-a:查看當前系統上所有網絡接口的狀態及詳細信息，包括非活動狀態的接口
CentOS 7 顯示參數詳解：
eno16777736：網卡名稱
inet：ip地址
netmask：子網掩碼
broadcast：廣播地址
UP：網卡表示激活狀態
BPOADCAST:支持廣播功能
MNLTICAST:支持組播功能
RUNNING：處於運行狀態
mtu：網卡最大傳輸單元
inet6：表示IPV6地址
ether：以太網地址，表示mac地址
txqueuelen：傳輸隊列長度
RX packets 5 bytes 440(440.0B)：接收到報文的數量、接收到報文的大小
RX errors：接收到錯誤報文的數量
dropped：丟包的數量
overruns：溢出的數量
TX packets 5 bytes 440 (440.0 B)：傳出報文的數量、傳出報文的大小
TX errors 0：傳出報文的錯誤數量
dropped：發送出去丟包的數量
CentOS 6 ifconfig顯示參數詳解
eth0：網卡名稱
Link encap：接口類型
inet addr：IP地址
Bcast：廣播地址
Mask：子網掩碼
inet6 addr：IPV6地址
UP：網卡表示激活狀態
BROADCAST：支持廣播功能
MULTICAST:支持組播功能
RUNNING：處於運行狀態
mtu：網卡的最大傳輸單元
ether：以太網地址，表示mac地址
txqueuelen：傳輸隊列長度
其他的同上
可以指定接口名稱，單獨查看
[root@localhost ~]# ifconfig eno16777736 eno16777736: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet 10.0.0.8 netmask 255.0.0.0 broadcast 10.255.255.255 inet6 fe80::20c:29ff:fe8e:1df3 prefixlen 64 scopeid 0x20<link> ether 00:0c:29:8e:1d:f3 txqueuelen 1000 (Ethernet) RX packets 57826 bytes 80877374 (77.1 MiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 14050 bytes 1058269 (1.0 MiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
修改網絡配置：
方法一：
# ifconfig eno16777736 10.0.0.8/8 up # ifconfig eno16777736: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet 10.0.0.8 netmask 255.0.0.0 broadcast 10.255.255.255 inet6 fe80::20c:29ff:fe8e:1df3 prefixlen 64 scopeid 0x20<link> ether 00:0c:29:8e:1d:f3 txqueuelen 1000 (Ethernet) RX packets 58044 bytes 80895700 (77.1 MiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 14176 bytes 1077665 (1.0 MiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions
注意：此配置僅臨時有效，重啓網絡服務或者重啓系統，內核會重讀配置文件
方法二：
# ifconfig eno16777736 10.0.0.8 netmask 255.0.0.0 up # ifconfig eno16777736: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet 10.0.0.8 netmask 255.0.0.0 broadcast 10.255.255.255 inet6 fe80::20c:29ff:fe8e:1df3 prefixlen 64 scopeid 0x20<link> ether 00:0c:29:8e:1d:f3 txqueuelen 1000 (Ethernet) RX packets 58194 bytes 80908451 (77.1 MiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 14248 bytes 1087805 (1.0 MiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
四: route 命令：查看即管理理由
命令格式：
route add [-net|-host] target [netmask NM] [gw GW] [dev]
-net:表示添加網絡路由
-host：表示添加主機路由
gw：爲默認網關
查看:
route -n
# route -n Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 0.0.0.0 10.0.0.254 0.0.0.0 UG 100 0 0 eno16777736 0.0.0.0 172.18.0.1 0.0.0.0 UG 101 0 0 eno33554984 10.0.0.0 0.0.0.0 255.0.0.0 U 100 0 0 eno16777736 172.18.0.0 0.0.0.0 255.255.0.0 U 100 0 0 eno33554984
添加路由：
# route add -net 192.168.0.0/24 gw 10.0.0.254 dev eno16777736 # route -n Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 0.0.0.0 10.0.0.254 0.0.0.0 UG 100 0 0 eno16777736 0.0.0.0 172.18.0.1 0.0.0.0 UG 101 0 0 eno33554984 10.0.0.0 0.0.0.0 255.0.0.0 U 100 0 0 eno16777736 172.18.0.0 0.0.0.0 255.255.0.0 U 100 0 0 eno33554984 192.168.0.0 10.0.0.254 255.255.255.0 UG 0 0 0 eno16777736 [root@localhost ~]#
刪除路由：
# route del -net 192.168.0.0/24 # route -n Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 0.0.0.0 10.0.0.254 0.0.0.0 UG 100 0 0 eno16777736 0.0.0.0 172.18.0.1 0.0.0.0 UG 101 0 0 eno33554984 10.0.0.0 0.0.0.0 255.0.0.0 U 100 0 0 eno16777736 172.18.0.0 0.0.0.0 255.255.0.0 U 100 0 0 eno33554984
五: netstat命令:打印網絡連接，路由表，接口等信息
netstat：
-t：tcp協議相關鏈接，和連接狀態
-u：udp協議相關連接
-w：raw socket相關的鏈接
-l：處於監聽狀態的鏈接
-a：顯示所有狀態
-n：以數字格式顯示IP和port
-e：擴展格式
-p：顯示相關的進程及PID
常用組合：
# netstat -tan Active Internet connections (servers and established) Proto Recv-Q Send-Q Local Address Foreign Address State tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN tcp 0 0 127.0.0.1:25 0.0.0.0:* LISTEN tcp 0 52 10.0.0.8:22 10.0.0.1:54649 ESTABLISHED tcp6 0 0 :::22 :::* LISTEN tcp6 0 0 ::1:25 :::* LISTEN # netstat -uan Active Internet connections (servers and established) Proto Recv-Q Send-Q Local Address Foreign Address State udp 0 0 0.0.0.0:12315 0.0.0.0:* udp 0 0 0.0.0.0:68 0.0.0.0:* udp6 0 0 :::26322 :::* # netstat -tunlp Active Internet connections (only servers) Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 1373/sshd tcp 0 0 127.0.0.1:25 0.0.0.0:* LISTEN 2491/master tcp6 0 0 :::22 :::* LISTEN 1373/sshd tcp6 0 0 ::1:25 :::* LISTEN 2491/master udp 0 0 0.0.0.0:12315 0.0.0.0:* 3510/dhclient udp 0 0 0.0.0.0:68 0.0.0.0:* 3510/dhclient udp6 0 0 :::26322 :::* 3510/dhclient
顯示路由表: netstat -rn
-r:顯示內核路由表
-n：數字格式顯示
# netstat -rn Kernel IP routing table Destination Gateway Genmask Flags MSS Window irtt Iface 0.0.0.0 10.0.0.254 0.0.0.0 UG 0 0 0 eno16777736 0.0.0.0 172.18.0.1 0.0.0.0 UG 0 0 0 eno33554984 10.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0 eno16777736 172.18.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eno33554984
顯示接口的統計數據：
netstat -i
# netstat -i Kernel Interface table Iface MTU RX-OK RX-ERR RX-DRP RX-OVR TX-OK TX-ERR TX-DRP TX-OVR Flg eno16777 1500 58877 0 0 0 14620 0 0 0 BMRU eno33554 1500 2530 0 0 0 173 0 0 0 BMRU lo 65536 5 0 0 0 5 0 0 0 LRU
註釋： Iface：接口
MTU:最大傳輸單元
RX-OK：成功接收報文的數量
RX-ERR：失敗接收報文的數量
RX-OVR：接收溢出報文的數量
TX-OK：成功傳輸報文的數量
TX-ERR：失敗傳輸報文的數量
TX-DRP：傳出丟棄的報文數量
TX-OVR：傳出溢出的報文數量
Flg：標誌
六：ifup/ifdown命令
CentOS 6：在使用ifdown命令時，禁用的接口用ifconfig命令顯示不出來，且顯示中沒有UP選項，如果想要展示要指定接口或者使用-a選項。
CentOS 7：在使用ifdown命令禁用網卡UP選項不會消失，但是IP沒有顯示
# ifdown eno33554984 Device 'eno33554984' successfully disconnected. eno33554984: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 ether 00:0c:29:8e:1d:fd txqueuelen 1000 (Ethernet) RX packets 3763 bytes 291395 (284.5 KiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 191 bytes 21542 (21.0 KiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 # ifup eno33554984 eno33554984: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet 172.18.100.109 netmask 255.255.0.0 broadcast 172.18.255.255 inet6 fe80::20c:29ff:fe8e:1dfd prefixlen 64 scopeid 0x20<link> ether 00:0c:29:8e:1d:fd txqueuelen 1000 (Ethernet) RX packets 3863 bytes 298512 (291.5 KiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 200 bytes 22508 (21.9 KiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
六：配置主機名：
hostname命令：
查看：hostname
配置：hostnem HOSTNAME
立即生效，重啓後無效
# hostname localhost.localdomain # hostname haha # hostname haha
hostnamectl命令(CentOS 7)
hostnamectl status:顯示當前主機名信息
hostnamectl set-hostname：設定主機名，永久有效
# hostnamectl status Static hostname: localhost.localdomain Transient hostname: haha Icon name: computer-vm Chassis: vm Machine ID: 3e995ea5a1f94852bf154b2a70b09756 Boot ID: 6e788705dc6646eea8fbf69c05befe64 Virtualization: vmware Operating System: CentOS Linux 7 (Core) CPE OS Name: cpe:/o:centos:centos:7 Kernel: Linux 3.10.0-327.el7.x86_64 Architecture: x86-64 # hostnamectl set-hostname ws # hostnamectl status Static hostname: ws Icon name: computer-vm Chassis: vm Machine ID: 3e995ea5a1f94852bf154b2a70b09756 Boot ID: 6e788705dc6646eea8fbf69c05befe64 Virtualization: vmware Operating System: CentOS Linux 7 (Core) CPE OS Name: cpe:/o:centos:centos:7 Kernel: Linux 3.10.0-327.el7.x86_64 Architecture: x86-64
配置文件：
CentOS6：/etc/sysconfig/network
HOSTNAME=<HOSTNAME> 永久有效，但不會立即生效
# hostname myserver # cat /etc/sysconfig/network NETWORKING=yes HOSTNAME=ws # hostname myserver
CentOS7：/etc/hostname
永久有效，但不會立即生效
# cat /etc/hostname wsssssssssssss # hostnamectl status Static hostname: wsssssssssssss Icon name: computer-vm Chassis: vm Machine ID: 3e995ea5a1f94852bf154b2a70b09756 Boot ID: 6e788705dc6646eea8fbf69c05befe64 Virtualization: vmware Operating System: CentOS Linux 7 (Core) CPE OS Name: cpe:/o:centos:centos:7 Kernel: Linux 3.10.0-327.el7.x86_64 Architecture: x86-64
七：配置DNS服務器指向：
配置文件：/etc/resolv.conf
nameserver DNS_SERVER_IP
# cat /etc/resolv.conf # Generated by NetworkManager nameserver 202.96.199.133 nameserver 8.8.8.8 nameserver 223.5.5.5
八：iproute家族配置管理
(1)ip命令
1> ip link set 改變設備屬性
# ip link set eno33554984 down # ip link show 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 2: eno16777736: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT qlen 1000 link/ether 00:0c:29:8e:1d:f3 brd ff:ff:ff:ff:ff:ff 3: eno33554984: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast state DOWN mode DEFAULT qlen 1000 link/ether 00:0c:29:8e:1d:fd brd ff:ff:ff:ff:ff:ff # ip link set eno33554984 up # ip link show 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 2: eno16777736: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT qlen 1000 link/ether 00:0c:29:8e:1d:f3 brd ff:ff:ff:ff:ff:ff 3: eno33554984: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT qlen 1000 link/ether 00:0c:29:8e:1d:fd brd ff:ff:ff:ff:ff:ff
2> 啓用或禁用多播功能：
multicast on 或multicast off
3>重命名接口
# ip link set eno33554984 down # ip link set eno33554984 name eno666777888 # ip link show 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 2: eno16777736: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT qlen 1000 link/ether 00:0c:29:8e:1d:f3 brd ff:ff:ff:ff:ff:ff 3: eno666777888: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast state DOWN mode DEFAULT qlen 1000 link/ether 00:0c:29:8e:1d:fd brd ff:ff:ff:ff:ff:ff
注意：改名時需要先關閉網卡設備
4> 設置mtu大小，默認爲1500
# ip link set eno666777888 mtu 1000 # ip link show 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 2: eno16777736: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT qlen 1000 link/ether 00:0c:29:8e:1d:f3 brd ff:ff:ff:ff:ff:ff 3: eno666777888: <BROADCAST,MULTICAST> mtu 1000 qdisc pfifo_fast state DOWN mode DEFAULT qlen 1000 link/ether 00:0c:29:8e:1d:fd brd ff:ff:ff:ff:ff:ff
5> ip link show 列出設備屬性
# ip link show 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 2: eno16777736: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT qlen 1000 link/ether 00:0c:29:8e:1d:f3 brd ff:ff:ff:ff:ff:ff 3: eno666777888: <BROADCAST,MULTICAST> mtu 1000 qdisc pfifo_fast state DOWN mode DEFAULT qlen 1000 link/ether 00:0c:29:8e:1d:fd brd ff:ff:ff:ff:ff:ff
(2)ip netns (僅適用於CentOS 7)
ip netns list: 列出所有的netns # ip netns list myspace ip netns add NAME: 創建指定的netns # ip netns add space1 # ip netns list space1 myspace ip netns del NAME: 刪除指定的netns # ip netns del myspace [root@localhost ~]# ip netns show space1 ip netns exec NAME COMMAND: 在指定的netns中運行命令 # ip link set eno666777888 netns space1 [root@localhost ~]# ip link show 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 2: eno16777736: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT qlen 1000 link/ether 00:0c:29:8e:1d:f3 brd ff:ff:ff:ff:ff:ff # 將某網卡加入到名稱空間後 使用IP link show查看，eno666777888已經被隱藏
(3)ip address協議地址管理
ip addr add：添加新的協議地址
[label name]:爲額外添加的地址指明接口別名
# ip addr add 10.0.0.100/8 dev eno33554984 label eno33554984:0
ip addr del：刪除端口別名
# ip addr del 10.0.0.100/8 dev eno33554984
ip addr show：查看協議地址
# ip addr show
ip addr flush：清除協議地址(清除某設備上的所有地址)
# ip addr flush # ip addr flush eno33554984
(4)ip route路由表管理
ip route add: 添加新的路由
# ip route add 172.18.100.111/24 via 172.18.64.1 dev eno33554984 # ip route default via 10.0.0.254 dev eno16777736 proto static metric 100 default via 172.18.0.1 dev eno33554984 proto static metric 101 10.0.0.0/8 dev eno16777736 proto kernel scope link src 10.0.0.8 metric 100 172.18.0.0/16 dev eno33554984 proto kernel scope link src 172.18.100.109 metric 100 172.18.100.111 via 172.18.64.1 dev eno33554984
ip route change：修改理由
# ip route change 172.18.100.111/24 via 172.18.64.2 dev eno33554984 # ip route default via 10.0.0.254 dev eno16777736 proto static metric 100 default via 172.18.0.1 dev eno33554984 proto static metric 101 10.0.0.0/8 dev eno16777736 proto kernel scope link src 10.0.0.8 metric 100 172.18.0.0/16 dev eno33554984 proto kernel scope link src 172.18.100.109 metric 100 172.18.100.111 via 172.18.64.2 dev eno33554984
ip route relace：改變或添加新的路由(如果沒有就新添加)
ip route delete：刪除路由
# ip route del 172.18.100.111/24 # ip route default via 10.0.0.254 dev eno16777736 proto static metric 100 default via 172.18.0.1 dev eno33554984 proto static metric 101 10.0.0.0/8 dev eno16777736 proto kernel scope link src 10.0.0.8 metric 100 172.18.0.0/16 dev eno33554984 proto kernel scope link src 172.18.100.109 metric 100
ip route get：查看一條路由
# ip route get 172.18.100.111/24
(5) ss 命令
用法與netstat相同
ss [option] [Filter]
選項：
-t:TCP協議相關連接
-u:UDP相關鏈接
-w:raw socket相關鏈接
-l:監聽狀態的鏈接
-a:所有狀態的鏈接
-n:數字格式
-p:相關程序及PID
-e:擴展格式信息
-m:內存用量
-o:計時器信息
# ss -tan State Recv-Q Send-Q Local Address:Port Peer Address:Port LISTEN 0 128 *:22 *:* LISTEN 0 100 127.0.0.1:25 *:* ESTAB 0 52 10.0.0.8:22 10.0.0.1:56452 LISTEN 0 128 :::22 :::* LISTEN 0 100 ::1:25 :::* # ss -uan State Recv-Q Send-Q Local Address:Port Peer Address:Port UNCONN 0 0 *:40478 *:* UNCONN 0 0 *:68 *:* UNCONN 0 0 :::53493 :::*
九：管理網絡屬性配置文件
(1)網卡配置文件: /etc/sysconfig/network-scripts/ifcfg-IFACE(接口)
命令方式修改：
setup
配置文件修改：
DEVICE=設備名稱
BOOTPROTO=激活接口時使用配置的協議屬性，有dhcp，static，none
HWADDR=網卡的硬件MAC地址
ONBOOT=是否開機啓動 yes 或 no
TYPE=接口類型，常見的有Ethernet、Bridge
IPADDR=IP地址
NETMASK=子網掩碼
GATEWAY=網關
DNS1=DNS服務器
UUID=設備的唯一標識
USERCTL=是否允許普通用戶控制此設備
PEERDNS=如果BOOTPROTO=dhcp，是否允許dhcp server分配的DNS服務器覆蓋本地手動指定的DNS服務器，默認允許
NM-CONTROLLED=是否啓用NetworkManager服務控制接口，在centos6中，一般選擇禁用，在centos7中啓用
示例：CentOS 7
IPV6INIT=yes BOOTPROTO=none DEVICE=eno16777736 ONBOOT=yes UUID=fc03aa9a-32b4-4d25-9576-288a0e3cd39a TYPE=Ethernet DEFROUTE=yes NAME="System eno16777736" PEERDNS=yes IPADDR=172.18.64.1 PREFIX=8 GATEWAY=172.18.0.1 DNS1=202.106.0.20 DNS2=172.18.0.1
示例：CentOS 6
DEVICE=eth0 HWADDR=00:0C:29:69:45:7B TYPE=Ethernet UUID=1e9d304f-319a-4467-ac3c-67159f182f33 ONBOOT=yes NM_CONTROLLED=yes BOOTPROTO=dhcp
(2)路由相關的配置文件：/etc/sysconfig/network-script/route-IFACE
支持兩種配置方式，但不可混用：
1>每行一個路由條目
# cat /etc/sysconfig/network-scripts/route-eno33554984 172.0.0.0/8 via 20.0.0.100 # systemctl restart network.service # route -n Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 0.0.0.0 172.18.0.1 0.0.0.0 UG 100 0 0 eno16777736 0.0.0.0 20.0.0.1 0.0.0.0 UG 101 0 0 eno33554984 20.0.0.0 0.0.0.0 255.255.255.0 U 100 0 0 eno33554984 172.0.0.0 20.0.0.100 255.0.0.0 UG 100 0 0 eno33554984 172.18.0.0 0.0.0.0 255.255.0.0 U 100 0 0 eno16777736
2>沒三行一個路由條目
# cat /etc/sysconfig/network-scripts/route-eno33554984 ADDRESS0=11.0.0.0 NETMASK0=255.0.0.0 GATEWAY0=20.0.0.100 # systemctl restart network.service # route -n Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 0.0.0.0 172.18.0.1 0.0.0.0 UG 100 0 0 eno16777736 0.0.0.0 20.0.0.1 0.0.0.0 UG 101 0 0 eno33554984 11.0.0.0 20.0.0.100 255.0.0.0 UG 100 0 0 eno33554984 20.0.0.0 0.0.0.0 255.255.255.0 U 100 0 0 eno33554984 172.18.0.0 0.0.0.0 255.255.0.0 U 100 0 0 eno16777736