The NetworkManager service in the ECS instance of the Linux causes a network exception -

Note

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Problem description

It cannot be connected to the internet. Run the route command to check whether the route is incorrect. The gateway of eth0 is a public IP address, but there is no error in the configuration file. The problem still exists after the system restarts in repair mode.

Cause

The NetworkManager service is started, leading to a network exception.

Solution

Note

Alibaba Cloud reminds you that:

When you perform operations that have risks, such as modifying instances or data, check the disaster recovery and fault tolerance capabilities of the instance to ensure data security.
If you modify the configurations and data of instances including but not limited to ECS and RDS instances, we recommend that you create snapshots or enable RDS log backup.
If you have authorized or submitted security information such as the logon account and password in the Alibaba Cloud Management console, we recommend that you modify such information in a timely manner.

Run the following command to disable the NetworkManager service:
```
systemctl stop NetworkManager
```

Run the following command to restart the network interface controller:
```
service network restart
```

References

NetworkManager is an ideal solution for portable computers and other removable computers. It supports top-level encryption types and standards for network connections, including 802.1x protected network connections. 802.1X is the port-based network access control IEEE Standard for Local and metropolitan area networks. With NetworkManager, you don't need to worry about configuring network interfaces and switching wired or wireless networks when moving. NetworkManager can automatically connect to known wireless networks or manage multiple network connections in parallel, and then use the fastest connection as the default connection. In addition, you can manually switch between available networks and use the applet in the system disk to manage network connections. Not only one connection can be activated, but also multiple connections can be activated at the same time. This allows the portable computer to remain connected through the wireless connection after being unplugged from the Ethernet connection. NetworkManager provides a complete and intuitive user interface that makes it easy to switch its network environment. However, NetworkManager is not applicable in the following cases.

The computer will provide network services to other computers in the network (for example, DHCP or DNS servers).

The computer is in a virtualized system.

Documentation

ECS operation instructions

Application scope

Elastic Compute Service