linux系统实现路由功能

概述：

1、在完成4台设备ip配置后默认路由有

路由器Rocky02上默认有：

• 192.168.10.0

• 172.20.0.0

路由器Rocky03上默认有：

• 192.168.10.0

• 10.0.0.0

主机Rocky01默认有：

• 172.20.0.0

• 0.0.0.0默认路由，配置网关后默认生成

主机Ubuntu01默认有：

• 10.0.0.0

• 0.0.0.0默认路由，配置网关后默认生成

所以:

• 如果主机Rocky01要访问路由器Rocky03的地址192.168.10.30，则需在路由器上配置一条返回路径的路由，否则虽然在Rocky02上有直连路由到Rocky03，但是无返回的路径

  #Rocky03新增路由配置
  [root@Rocky03 ~]# route add -net 172.20.0.0/24 gw 192.168.10.20 dev eth0

• 如果主机ubuntu01要访问路由器Rocky02的地址172.20.0.20，则需在路由器Rocky02上配置一条返回路径的路由，否则虽然在Rocky03上有直连路由到Rocky02，但是无返回的路径

  #Rocky02新增路由配置
  [root@Rocky02_v7 ipv4]$ route add -net 10.0.0.0/24 gw 192.168.10.30 dev eth0

• 如果两台主机需互访，则需在两台路由器上均配置各自到两台主机的路由，则为如上两条路由

配置两台主机

1、Rock01，配置一张仅主机网卡，vmnet2

#配置IP
[root@Rocky01 network-scripts]$ cat ifcfg-eth0
TYPE=Ethernet
BOOTPROTO=static
NAME=eth0
DEVICE=eth0
IPADDR=172.20.0.10
GATEWAY=172.20.0.20
PREFIX=24
ONBOOT=yes
​
#查看IP
[root@Rocky01 ~]$ ip a show eth0 
2: eth0:  mtu 1500 qdisc mq state UP group default qlen 1000
    link/ether 00:0c:29:6c:4b:c9 brd ff:ff:ff:ff:ff:ff
    inet 172.20.0.10/24 brd 172.20.0.255 scope global noprefixroute eth0
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fe6c:4bc9/64 scope link 
       valid_lft forever preferred_lft forever
       
#查看路由
[root@Rocky01 network-scripts]$ route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         172.20.0.20     0.0.0.0         UG    100    0        0 eth0
172.20.0.0      0.0.0.0         255.255.255.0   U     100    0        0 eth0
192.168.122.0   0.0.0.0         255.255.255.0   U     0      0        0 virbr0
​

2、Ubuntu01，配置一张NAT网卡，vmnet8

#配置IP
root@ubuntu2204-1:/etc/netplan# cat 00-installer-config.yaml
# This is the network config written by 'subiquity'
network:
  renderer: NetworkManager
  renderer: networkd
  ethernets:
    ens33:
      addresses: [10.0.0.10/24]
      gateway4: 10.0.0.2
      dhcp4: false
      nameservers: 
        addresses: [10.0.0.2]
  version: 2
​
#查看IP
root@ubuntu2204-1:/etc/netplan# ip a show eth0 
2: eth0:  mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 00:0c:29:8c:86:cb brd ff:ff:ff:ff:ff:ff
    altname enp2s1
    altname ens33
    inet 10.0.0.10/24 brd 10.0.0.255 scope global eth0
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fe8c:86cb/64 scope link 
       valid_lft forever preferred_lft forever

配置路由器01

3、Rock02作为路由器01，设置仅主机网卡vmnet1，vmnet2

网卡1（eth0） vmnet1与另一路由器相连

网卡2（eth1） vmnet2与主机相连

#网卡1（eth0） vmnet1
[root@Rocky02_v7 network-scripts]$ cat ifcfg-eth0
BOOTPROTO=static
NAME=eth0
DEVICE=eth0
IPADDR=192.168.10.20
PREFIX=24
ONBOOT=yes
​
#网卡2（eth1） vmnet2
[root@Rocky02_v7 network-scripts]$ cat ifcfg-eth1 
BOOTPROTO=static
NAME=eth1
DEVICE=eth1
IPADDR=172.20.0.20
PREFIX=24
ONBOOT=yes
​
#查看IP
[root@Rocky02_v7 network-scripts]$ ip a show 
​
2: eth0:  mtu 1500 qdisc mq state UP group default qlen 1000
    link/ether 00:0c:29:9c:01:da brd ff:ff:ff:ff:ff:ff
    inet 192.168.10.20/24 brd 192.168.10.255 scope global noprefixroute eth0
       valid_lft forever preferred_lft forever
​
4: eth1:  mtu 1500 qdisc mq state UP group default qlen 1000
    link/ether 00:0c:29:9c:01:e4 brd ff:ff:ff:ff:ff:ff
    inet 172.20.0.20/24 brd 172.20.0.255 scope global noprefixroute eth1
       valid_lft forever preferred_lft forever
       
​

配置路由器02

3、Rock03作为路由器02，设置仅主机网卡vmnet1，vmnet8

网卡1（eth0） vmnet1与另一路由器相连

网卡2（eth1） vmnet8与主机相连

#网卡1（eth0） vmnet1
[root@Rocky03 network-scripts]# cat ifcfg-eth0
BOOTPROTO=static
NAME=eth0
DEVICE=eth0
IPADDR=192.168.10.30
PREFIX=24
ONBOOT=yes
​
#网卡2（eth1） vmnet8
[root@Rocky03 network-scripts]# cat ifcfg-eth1
BOOTPROTO=static
NAME=eth1
DEVICE=eth1
IPADDR=10.0.0.30
PREFIX=24
DNS=10.0.0.2
ONBOOT=yes
​
#查看IP
[root@Rocky03 network-scripts]# ip a show 
2: eth0:  mtu 1500 qdisc mq state UP group default qlen 1000
    link/ether 00:0c:29:44:13:14 brd ff:ff:ff:ff:ff:ff
    inet 192.168.10.30/24 brd 192.168.10.255 scope global noprefixroute eth0
       valid_lft forever preferred_lft forever
​
4: eth1:  mtu 1500 qdisc mq state UP group default qlen 1000
    link/ether 00:0c:29:44:13:1e brd ff:ff:ff:ff:ff:ff
    inet 10.0.0.30/24 brd 10.0.0.255 scope global noprefixroute eth1
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fe44:131e/64 scope link 
       valid_lft forever preferred_lft foreve

在路由器上添加路由

#两台路由器添加路由前，两台主机均无法互访
root@ubuntu2204-1:/etc/netplan# ping 172.20.0.10
PING 172.20.0.10 (172.20.0.10) 56(84) bytes of data.
From 10.0.0.30 icmp_seq=1 Destination Net Unreachable
From 10.0.0.30 icmp_seq=2 Destination Net Unreachable
​
​
​
[root@Rocky01 network-scripts]$ ping 10.0.0.10
PING 10.0.0.10 (10.0.0.10) 56(84) bytes of data.
From 172.20.0.20 icmp_seq=1 Destination Net Unreachable
​
​
#查看路由
1、主机Rocky01，默认路由为配置IP时如有配置网关，则会生成
[root@Rocky01 network-scripts]$ route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         172.20.0.20     0.0.0.0         UG    100    0        0 eth0
172.20.0.0      0.0.0.0         255.255.255.0   U     100    0        0 eth0
192.168.122.0   0.0.0.0         255.255.255.0   U     0      0        0 virbr0
​
2、主机ubuntu01
root@ubuntu2204-1:/etc/netplan# route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         10.0.0.30       0.0.0.0         UG    0      0        0 eth0
10.0.0.0        0.0.0.0         255.255.255.0   U     0      0        0 eth0
10.0.0.0        0.0.0.0         255.255.255.0   U     0      0        0 eth1
​
3、路由器Rocky02
[root@Rocky02_v7 network-scripts]$ route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
172.20.0.0      0.0.0.0         255.255.255.0   U     101    0        0 eth1
192.168.10.0    0.0.0.0         255.255.255.0   U     102    0        0 eth0
​
4、路由器Rock03
[root@Rocky03 ~]# route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
10.0.0.0        0.0.0.0         255.255.255.0   U     101    0        0 eth1
192.168.10.0    0.0.0.0         255.255.255.0   U     102    0        0 eth0
​

在两台路由器分别添加路由

#Rocky02
添加路由前的路由表
[root@Rocky02_v7 ipv4]$ route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
172.20.0.0      0.0.0.0         255.255.255.0   U     101    0        0 eth1
192.168.10.0    0.0.0.0         255.255.255.0   U     102    0        0 eth0
​
添加路由
[root@Rocky02_v7 ipv4]$ route add -net 10.0.0.0/24 gw 192.168.10.30 dev eth0
​
查看添加路由后的路由表
[root@Rocky02_v7 ipv4]$ route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
10.0.0.0        192.168.10.30   255.255.255.0   UG    0      0        0 eth0
172.20.0.0      0.0.0.0         255.255.255.0   U     101    0        0 eth1
192.168.10.0    0.0.0.0         255.255.255.0   U     102    0        0 eth0
​
​
​
#Rocky03
添加路由前的路由表
[root@Rocky03 ~]# route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
10.0.0.0        0.0.0.0         255.255.255.0   U     101    0        0 eth1
192.168.10.0    0.0.0.0         255.255.255.0   U     102    0        0 eth0
​
添加路由
[root@Rocky03 ~]# route add -net 172.20.0.0/24 gw 192.168.10.20 dev eth0
​
查看添加路由后的路由表
[root@Rocky03 ~]# route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
10.0.0.0        0.0.0.0         255.255.255.0   U     101    0        0 eth1
172.20.0.0      192.168.10.20   255.255.255.0   UG    0      0        0 eth0
192.168.10.0    0.0.0.0         255.255.255.0   U     102    0        0 eth0

测试：

[root@Rocky01 network-scripts]$ ping 10.0.0.10
PING 10.0.0.10 (10.0.0.10) 56(84) bytes of data.
64 bytes from 10.0.0.10: icmp_seq=1 ttl=62 time=1.08 ms
64 bytes from 10.0.0.10: icmp_seq=2 ttl=62 time=3.79 ms
​
root@ubuntu2204-1:/etc/netplan# ping 172.20.0.10
PING 172.20.0.10 (172.20.0.10) 56(84) bytes of data.
64 bytes from 172.20.0.10: icmp_seq=1 ttl=62 time=1.56 ms
64 bytes from 172.20.0.10: icmp_seq=2 ttl=62 time=3.30 ms