管理IPv4网络连接

1. 使用 nmcli 检查所有连接

[root@desktop1 ~]# nmcli connection
NAME                UUID                                  TYPE            DEVICE
eno33554960         5be7dba9-6baf-407d--88c034fb7e9c  --ethernet  --
Bridge eno16777736  d2d68553-f97e--7a26-b34a26f29318  bridge          br0
System eno16777736  8863e6a4-94da-488b-9de7-160b3b5951c8  --ethernet  eno16777736
virbr0              b50fb815-6e76-49d3-937b-bbe0b7b137c1  bridge          virbr0
eno50332184         8e064c29-9aad-433c-a75e-1f80e6051018  --ethernet  --
[root@desktop1 ~]# 

2. 删除‘virbr0’外的所有 connection

[root@desktop1 ~]# nmcli connection delete 'Bridge eno16777736' 'System eno16777736' 'eno50332184'

3.  使用 ip addr 和 ping 确认你的 desktop 无法访问网络

[root@desktop1 ~]# ip addr
: lo: <LOOPBACK,UP,LOWER_UP> mtu  qdisc noqueue state UNKNOWN
    link/loopback ::::: brd :::::
    inet 127.0.0.1/ scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::/ scope host
       valid_lft forever preferred_lft forever
: eno16777736: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu  qdisc pfifo_fast state UP qlen
    link/ether :0c:::d3:7a brd ff:ff:ff:ff:ff:ff
: eno33554960: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu  qdisc pfifo_fast state UP qlen
    link/ether :0c:::d3: brd ff:ff:ff:ff:ff:ff
: eno50332184: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu  qdisc pfifo_fast state UP qlen
    link/ether :0c:::d3:8e brd ff:ff:ff:ff:ff:ff
: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu  qdisc noqueue state DOWN
    link/ether a2::a8:b3:ca: brd ff:ff:ff:ff:ff:ff
    inet 192.168.122.1/ brd 192.168.122.255 scope global virbr0
       valid_lft forever preferred_lft forever
[root@desktop1 ~]# ping 192.168.0.254
connect: Network is unreachable
[root@desktop1 ~]# 

4. 创建一个新的 connection，名称为 net1，接口为你的 desktop 的第一个网卡(eno16777736)，开启自动连接 (查看网卡信息：nmcli device status)

[root@desktop1 ~]# nmcli connection add con-name net1 type ethernet ifname eno16777736 autoconnect yes
Connection 'net1' (4e2cba1b-b8ff--812f-9772d2a5cdd8) successfully added.
[root@desktop1 ~]# 

5. 修改 net1，IPv4 地址为手动地址，地址是 192.168.0.1/24 ，网关和 dns 是 192.168.0.254

[root@desktop1 ~]# nmcli connection modify net1 ipv4.addresses '192.168.0.1/24 192.168.0.254' ipv4.dns '192.168.0.254' ipv4.method manual
[root@desktop1 ~]# 

6. 重新启动 net1，确认 IP 地址是静态 IP 地址

[root@desktop1 ~]# nmcli connection up net1
Connection successfully activated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/)
[root@desktop1 ~]# ip addr
: lo: <LOOPBACK,UP,LOWER_UP> mtu  qdisc noqueue state UNKNOWN
    link/loopback ::::: brd :::::
    inet 127.0.0.1/ scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::/ scope host
       valid_lft forever preferred_lft forever
: eno16777736: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu  qdisc pfifo_fast state UP qlen
    link/ether :0c:::d3:7a brd ff:ff:ff:ff:ff:ff
    inet 192.168.0.1/ brd 192.168.0.255 scope global eno16777736
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fe94:d37a/ scope link
       valid_lft forever preferred_lft forever
: eno33554960: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu  qdisc pfifo_fast state UP qlen
    link/ether :0c:::d3: brd ff:ff:ff:ff:ff:ff
: eno50332184: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu  qdisc pfifo_fast state UP qlen
    link/ether :0c:::d3:8e brd ff:ff:ff:ff:ff:ff
: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu  qdisc noqueue state DOWN
    link/ether a2::a8:b3:ca: brd ff:ff:ff:ff:ff:ff
    inet 192.168.122.1/ brd 192.168.122.255 scope global virbr0
       valid_lft forever preferred_lft forever
[root@desktop1 ~]# ip route
default via 192.168.0.254 dev eno16777736  proto static  metric
192.168.0.0/ dev eno16777736  proto kernel  scope link  src 192.168.0.1
192.168.122.0/ dev virbr0  proto kernel  scope link  src 192.168.122.1
[root@desktop1 ~]# ping 192.168.0.254
PING 192.168.0.254 (192.168.0.254) () bytes of data.
 bytes from 192.168.0.254: icmp_seq= ttl= time=0.688 ms
 bytes from 192.168.0.254: icmp_seq= ttl= time=0.658 ms
^C
--- 192.168.0.254 ping statistics ---
 packets transmitted,  received, % packet loss, time 2003ms
rtt min/avg/max/mdev = 0.658/0.681/0.698/0.027 ms
[root@desktop1 ~]# 

7. 修改 net1，增加一个 dns 地址为 192.168.1.254

[root@desktop1 ~]# nmcli connection modify net1 +ipv4.dns '192.168.1.254'
[root@desktop1 ~]# nmcli connection up net1
Connection successfully activated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/)
[root@desktop1 ~]# cat /etc/resolv.conf
# Generated by NetworkManager
search example.com
nameserver 192.168.0.254
nameserver 192.168.1.254
[root@desktop1 ~]# 

8. 修改 net1，删除上一步配置的 dns192.168.1.254，但保留 192.168.0.254

[root@desktop1 ~]# nmcli connection modify net1 -ipv4.dns '192.168.1.254'
[root@desktop1 ~]# nmcli connection up net1
Connection successfully activated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/)
[root@desktop1 ~]# cat /etc/resolv.conf
# Generated by NetworkManager
search example.com
nameserver 192.168.0.254
[root@desktop1 ~]# 

9. 编辑 hosts 文件，确保访问“myserver”会被解析为 192.168.0.(100+X )

[root@desktop1 ~]# echo '192.168.0.101 myserver' >> /etc/hosts
[root@desktop1 ~]# ping myserver
PING myserver (192.168.0.101) () bytes of data.
 bytes from myserver (192.168.0.101): icmp_seq= ttl= time=0.679 ms
 bytes from myserver (192.168.0.101): icmp_seq= ttl= time=0.509 ms
 bytes from myserver (192.168.0.101): icmp_seq= ttl= time=0.595 ms
 bytes from myserver (192.168.0.101): icmp_seq= ttl= time=0.773 ms
^C
--- myserver ping statistics ---
 packets transmitted,  received, % packet loss, time 3004ms
rtt min/avg/max/mdev = 0.509/0.639/0.773/0.097 ms
[root@desktop1 ~]#