Alibaba Cloud ECS Troubleshooting
Help you solve the problems encountered in the use of ECS.
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How to Troubleshoot the Failure of ECS to Connect to Linux Instances
There are many possible reasons for SSH remote login failure, such as PAM security framework, security group, and SSH configuration.
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ECS cannot connect to the Linux instance
The PAM security framework of the Linux system can load relevant security modules to control access to cloud server account policies and login policies.
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Step 1-4 | There is no clear error message when the remote connection fails
Use the Workbench tool provided by Alibaba Cloud to log in remotely. The Workbench tool will return specific error messages and solutions when an exception occurs in the remote login.
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Step 5-8 | There is no clear error message when the remote connection fails
Note This troubleshooting can be performed only when the firewall is authorized to be disabled. Please confirm whether the firewall is closed, if not, fix it by adjusting the firewall configuration policy.
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Step 9-13| There is no clear error message when the remote connection fails
When unable to remotely connect to a Windows instance normally, it may be due to CPU load, insufficient bandwidth, or insufficient memory.
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Workbench remote connection problem for Linux system instance
When using the Workbench tool to remotely connect to a Linux instance, it prompts that the connection has timed out. What should I do?
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Workbench remote connection problem for Windows system instance
What should I do if the remote connection to the Windows instance through the Workbench tool prompts that the connection has timed out?
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Problems connecting to instances remotely via VNC
A black screen appears after connecting to the console VNC, indicating that the system is hibernating.
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What should I do if the error message "Permission denied, please try again" is displayed
When logging in to the ECS instance of the Linux system through the local SSH client, even if the correct password is entered, an error message similar to the following appears.
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What should I do if an error message is displayed when logging in to a Linux instance
When logging in to the Linux instance through the SSH client and confirming that the user name and password are correct, the following error message is encountered.
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How to keep process running after SSH client disconnects?
This article describes how to keep the process running after disconnecting the SSH client in the ECS instance of the Linux system.
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What should I do if the error "Access denied" is displayed?
When a third-party SSH client logs in to a Linux instance, an "Access denied" error is displayed. Execute cat /var/log/secure to view the login log, and you will find information similar to the following.
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Unable to remotely connect to the ECS instance of the Linux system
This article mainly introduces the reasons and solutions for the "error: Unable to load host key: /etc/ssh/ssh_host_rsa_key" error displayed on an ECS instance remotely connected to a Linux system.
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What should I do if the error "No supported authentication methods available" is displayed
This article describes the cause and solution of the error "No supported authentication methods available (server sent: publickey,gssapi-keyex,gssapi-with-mic)" displayed when using a third-party SSH client to remotely connect to a Linux instance.
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What should I do if the freeze occurs when connecting to a Linux instance remotely
It takes a long time to connect to the Linux instance using SSH. After entering the username and password, it will freeze for a while before entering the system. During the freezing period, use the Ctrl+C command to skip the freezing and enter the instance normally.
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What should I do if the error message "error while loading shared libraries" is displayed
When an ECS instance of the Linux system starts the SSH service, an error message similar to the following is displayed.
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What should I do if the error "requirement "uid >= 1000" not met by user "root"is displayed?
When logging in to the ECS instance of the Linux system through the local SSH client, even if the correct password is entered, the login cannot be performed normally. Execute cat /var/log/secure to view the secure log.
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What Errors Are Prompted When Starting the SSH Service
What should I do if the error "fatal: Cannot bind any address" is displayed when I start the SSH service in the ECS instance of the Linux system?
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What should I do if the error "Too many authentication failures" is displayed?
When using a third-party SSH client to remotely connect to a Linux instance, the connection fails and the message "Too many authentication failures" is displayed.
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What to Do If an Error Is Displayed When Starting the SSH Service
What should I do if the error "This account is currently not available." is displayed when I use SSH to remotely connect to the ECS instance of the Linux system?
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What should I do if the error "Failed to start OpenSSh server daemon" is displayed?
In the ECS instance of the Linux system, the SSH service (sshd.service) cannot be started. Run systemctl status sshd.Service to view the SSH service, and the error "Failed to start OpenSSh server daemon" is displayed.
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What should I do if the error "fatal: mm_request_send: write: Broken pipe" is displayed?
When executing the SSH command in the ECS instance of the Linux system, the error "fatal: mm_request_send: write: Broken pipe" is displayed.
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What should I do if the error "Maximum amount of failed attempts was reached" is displayed?
When using the SSH client to remotely connect to the ECS instance of the Linux system, the error "Maximum amount of failed attempts was reached" is displayed.
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What should I do if the "Bad configuration options" error is displayed?
When the SSH service is started on the ECS instance of the Linux system, information similar to the following may appear in the command line or secure log.
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What should I do if the SSH login or data transmission speed is very slow?
This article introduces the causes and solutions for the slow SSH login or data transmission speed in the ECS instance of the Linux system.
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A Quick Troubleshooting Method for Unable to Access the Website Running in the ECS Instance
There are many reasons for not being able to access the website running on the ECS instance. Here are some common causes of problems. The specific reasons are subject to the on-site investigation results.
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The website running on the Linux instance cannot be accessed because TCP port 80 and the web service are unavailable
Note The following steps use the CentOS 7 operating system as an example. For specific operations, please refer to your actual operating system.
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The website running on the Windows instance cannot be accessed because TCP port 80 and the web service are unavailable
Note The following steps use the Windows Server 2012 R2 operating system as an example. For specific operations, please refer to your actual operating system.
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Web service unavailable
You can view the CPU and memory information of the process in the task manager, and locate the abnormal process.
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What should I do if the Windows instance cannot access the external network?
The cause of this problem is similar to the problem that the Windows instance fails to access the network through the outside world. For common problems, please refer to the following.
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What should I do if Internet Explorer cannot be used to access external websites in a Windows instance?
In a Windows instance, you cannot use the Internet Explorer browser that comes with the operating system to access external websites.
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Prompt "500 - Internal Server Error", how to deal with it?
When accessing an IIS-based website deployed on a Windows instance, "500 - Internal Server Error" is displayed.
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IIS website is set to prohibit direct access through IP address
How Do I Disable Direct Access Through IP Addresses in IIS Websites of Windows Instances?
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How to deal with the "403.14-Forbidden" error
On a Windows instance, the error "HTTP Error 403.14-Forbidden Web server is configured not to list the contents of this directory" is displayed when accessing a website built on IIS.
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What should I do if the "Nginx 502 bad gateway" error is displayed when accessing a website in an ECS instance?
The "Nginx 502 Bad Gateway" error indicates that the php-cgi process of the access request has started to execute, but the execution has not been completed due to reasons such as failure to read resources, resulting in the termination of the php-cgi process.
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Visiting WordPress website prompts" Error establishing database connection"
This article introduces the causes and solutions of the error message "An error occurred while establishing a database connection" when accessing a WordPress website through a browser.
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How to handle the inability to log in to the Pagoda Service Panel console through a browser on an ECS instance?
The Pagoda service panel console is deployed in the ECS instance, but the Pagoda service panel console cannot be accessed by entering the public network IP: port of the ECS instance through the browser, as shown in the figure: Cannot access the Pagoda panel problem phenomenon
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What should I do if the enhanced security configuration is blocking content from the following websites?
On the cloud server ECS or lightweight application server of the Windows operating system, when using the IE browser to open the website, the following error is displayed.
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How to deal with slow access to external websites or TCP connection retransmission problems
This article introduces the description, cause and solution of the problem of slow access to external websites or retransmission of TCP connections after the ECS instance of the Windows Server 2012 system enables the ECN (Explicit Congestion Notification) function.
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Time_Wait connection is not released, resulting in failure to access the external network
This article introduces the problem description, cause and solution of the problem that the Time_Wait connection of the Windows instance is not released, resulting in the failure to access the external network.
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How to deal with connect upstream time out error?
This article introduces the symptoms, causes, and solutions of the "502" and "connect upstream time out" errors reported when using Nginx to access the webpage because the local loopback network card (lo) is not started.
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How to deal with "Bad Request (Invalid Hostname)" error?
This article introduces the description, cause, and solution of the "Bad Request (Invalid Hostname)" error when accessing a website created using IIS (Internet Information Services) on a Windows instance.
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Slow when performing operations on the server after remotely connecting to a Windows Server 2003 instance
When remotely connecting to a Windows Server 2003 instance, it is normal to log in to the server using VNC, but when logging in to the server using other remote connection methods, the speed of opening programs and browsing websites is slow. This article introduces the solution in this scenario.
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The error "absolute physical path xxx is not allowed in 500.19-xxx" appears
This article introduces the description, cause and solution of the error "Absolute physical path xxx is not allowed in 500.19-xxx" when accessing a website deployed using IIS (Internet Information Services) on a Windows instance.
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Custom domain name resolution inside a Windows instance
A website cannot be accessed through a browser inside the Windows instance, but it can be accessed normally on other devices. The investigation found that the custom domain name resolution inside the Windows instance is inconsistent with the domain name resolution of the local network.
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How to deal with the "ERR_CONNETCION_TIMED_OUT" error?
When you use a browser on a local device or an ECS instance to access a website deployed on an ECS instance, it may appear that accessing the website through the http://domain name is normal, but accessing the website through the https://domain name prompts "ERR_CONNETCION_TIMED_OUT" situation
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Migrating a website connected to a CDN to a Windows instance
This article describes the problem description, cause, and solution to the problem that the connection is refused when a website connected to the CDN is migrated to a Windows instance.
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Introduction to Common Kernel Network Parameters and Handling of Common Problems in Linux System
This article introduces common Linux system kernel network parameters and solutions to common problems.
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Handling of Common Problems in Linux System
Why are there a large number of TCP connections in the FIN_WAIT2 state in the ECS instance of the Linux system?
