Centos7 add static routes

Environment Description:

CPU name	Operating system version	ip	Default Gateway	Name card	1 destination address	2 destination address
centos7.6	Centos 06/07/1810	172.27.9.135	172.27.9.254	ens33	172.28.105.0/24	172.28.214.17/32

A temporary way

1. Check the routing and ip

[root@centos7 ~]# route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         172.27.9.254    0.0.0.0         UG    100    0        0 ens33
10.244.0.0      10.244.0.0      255.255.255.0   UG    0      0        0 flannel.1
10.244.1.0      0.0.0.0         255.255.255.0   U     0      0        0 cni0
10.244.2.0      10.244.2.0      255.255.255.0   UG    0      0        0 flannel.1
172.17.0.0      0.0.0.0         255.255.0.0     U     0      0        0 docker0
172.27.9.0      0.0.0.0         255.255.255.0   U     100    0        0 ens33
[root@centos7 ~]# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default 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: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 00:0c:29:7a:68:80 brd ff:ff:ff:ff:ff:ff
    inet 172.27.9.135/24 brd 172.27.9.255 scope global noprefixroute ens33
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fe7a:6880/64 scope link 
       valid_lft forever preferred_lft forever
3: docker0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default 
    link/ether 02:42:bc:7f:3b:6b brd ff:ff:ff:ff:ff:ff
    inet 172.17.0.1/16 brd 172.17.255.255 scope global docker0
       valid_lft forever preferred_lft forever
4: flannel.1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1450 qdisc noqueue state UNKNOWN group default 
    link/ether 96:fb:38:22:16:63 brd ff:ff:ff:ff:ff:ff
    inet 10.244.1.0/32 scope global flannel.1
       valid_lft forever preferred_lft forever
    inet6 fe80::94fb:38ff:fe22:1663/64 scope link 
       valid_lft forever preferred_lft forever
5: cni0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1450 qdisc noqueue state UP group default qlen 1000
    link/ether a6:93:72:c1:bc:6e brd ff:ff:ff:ff:ff:ff
    inet 10.244.1.1/24 scope global cni0
       valid_lft forever preferred_lft forever
    inet6 fe80::a493:72ff:fec1:bc6e/64 scope link 
       valid_lft forever preferred_lft forever
6: vethcc8de5ce@if3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1450 qdisc noqueue master cni0 state UP group default 
    link/ether 1e:70:7e:e4:47:c6 brd ff:ff:ff:ff:ff:ff link-netnsid 0
    inet6 fe80::1c70:7eff:fee4:47c6/64 scope link 
       valid_lft forever preferred_lft forever

2. Add a static route

Add a static route to the destination address of 1

[root@centos7 ~]# ip route add 172.28.105.0/24 via 172.27.9.254 dev ens33

 
Add a static route to the destination address 2

[root@centos7 ~]# ip route add 172.28.214.17/32 via 172.27.9.254 dev ens33

View the routing information

[root@centos7 ~]# route -n

Second, permanent way

There are two forms of realization

1. To achieve form 1

Add or edit the configuration file route-interfacename, interfacename name for the network card, this is ens33

[root@centos7 ~]# view /etc/sysconfig/network-scripts/route-ens33
ADDRESS0=172.28.105.0
NETMASK0=255.255.255.0
GATEWAY0=172.27.9.254
ADDRESS1=172.28.214.17
NETMASK1=255.255.255.255
GATEWAY1=172.27.9.254

Note that Nos. 0 and 1
 
restart network

[root@centos7 ~]# systemctl restart network

2. Realization 2

[root@centos7 ~]# view /etc/sysconfig/network-scripts/route-ens33 
172.28.105.0/24 via 172.27.9.254 dev ens33
172.28.214.17/32 via 172.27.9.254 dev ens33

Restart Network

[root@centos7 ~]# systemctl restart network

Third, remove a static route

1. Delete Route

[root@centos7 ~]# ip route del 172.28.105.0/24
[root@centos7 ~]# ip route del 172.28.214.17/32
[root@centos7 ~]# route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         172.27.9.254    0.0.0.0         UG    100    0        0 ens33
10.244.0.0      10.244.0.0      255.255.255.0   UG    0      0        0 flannel.1
10.244.1.0      0.0.0.0         255.255.255.0   U     0      0        0 cni0
10.244.2.0      10.244.2.0      255.255.255.0   UG    0      0        0 flannel.1
172.17.0.0      0.0.0.0         255.255.0.0     U     0      0        0 docker0
172.27.9.0      0.0.0.0         255.255.255.0   U     100    0        0 ens33

This approach will immediately remove static routing

2. Clear configuration

rm route-ens33 or echo> route-ens33 routing entry or comment that profile

#ADDRESS0=172.28.105.0
#NETMASK0=255.255.255.0
#GATEWAY0=172.27.9.254
#ADDRESS1=172.28.214.17
#NETMASK1=255.255.255.255
#GATEWAY1=172.27.9.254

The next time you reboot, static routing permanently deleted

IV Notes

• Add a permanent static routing should pay attention to numbers, add sequentially from 0, the serial number can not jump, only one route if the number is 0;
• Two kinds of permanent way can not be mixed, otherwise, the route configuration entries will not be fully effective;