Testing Basic connectivity Using Telnet¶
To install Telnet, select start, type and select the resultant , (Alternatively, you can press the keys on your keyboard simultaneously to bring up a run dialogue box)
Type in the run box as below and select “OK”
The telnet command will now be active and usable via any Command Prompt window, or PowerShell window.
Open a Command Prompt or a PowerShell window by selecting start and selecting your chosen console, once the console has opened, type , for example , and press enter on your keyboard.
If the connection is established, you will receive a response from the remote server as demonstrated below
If however, you are presented with a blank window, this could mean that the connection could not be established correctly, at this point, it is advised to review firewall rules etc to ensure that appropriate access is allowed to and from your target IP.
Next Article > Creating Appropriate permissions
On your Windows 11 PC, you can enable Telnet using PowerShell. It is a single line command that you have to run in PowerShell to enable the Telnet client.
There are multiple ways to enable Telnet on your Windows computers. Some of them include:
- Enable Telnet using Command Prompt
- Install Telnet Client from control panel
- Use PowerShell to enable Telnet Windows feature
PowerShell is the easiest method to enable Telnet because it requires running a single command on Windows 11 PC.
Telnet consists of two services – A Telnet Client and Telnet Server. A Telnet Client allows a computer to connect to a remote Telnet server and run applications on that server.
Telnet is included with several operating systems like Windows 11, Windows 10. However like it said before it is better to use SSH instead of telnet.
Let see the steps to enable Telnet using PowerShell:
- Click Start and launch the PowerShell as administrator.
- Run the command Enable-WindowsOptionalFeature -Online -FeatureName TelnetClient
- This command enables the Telnet client on your Windows computer.
After you enable Telnet client on Windows 11 PC, you don’t need to restart your computer.
To verify if the Telnet is enabled on Windows 11 computer, run the command Telnet
Editorial Staff is a team of experts with several years of experience in Configuration Manager, Intune, Windows Server, Windows 365, and other related topics.
Using Telnet or Powershell to troubleshoot connectivity between CCS components.
Updated On:
Products
Control Compliance Suite
Control Compliance Suite Standards Server
Control Compliance Suite Standards Module
Issue/Introduction
Control Compliance Suite (CCS)
Environment
CCS Network Ports: CCS 12.6.x Network Ports
Common listening ports for the different CCS components:
All CCS Managers: 5600
All Windows agents: 5601
All UNIX/Linux agents: 5600
Resolution
How use Telnet or Powershell to test connectivity
It is best to test communication from each server that is running a CCS component. Example: from ManagerA to ManagerB, and then from ManagerB to ManagerA.
How to run Telnet:
Telnet syntax:
telnet <Example.com> <listening_port>
(NOTE: You can use the hostname, FQDN, or IP of the CCS component you would like to connect to test)
Example.
telnet Example.com 5600 (this example shows an attempt to telnet to the target server EXAMPLE.COM using port 5600)
If a blank screen appears with no errors a telnet session has been established. Press another key to break the connection and return to a command prompt.
How to use Powershell to test connectivity
Syntax:
Test-NetConnection -Port <Port_number> -ComputerName Example -InformationLevel Detailed
Managers listens on port 5600
Windows agent listens on port 5601
Unix\Linux agent listens on port 5600
PS C:\Users\####> Test-NetConnection -Port 5601 -ComputerName 192.0.2.1 -InformationLevel Detailed
WARNING: TCP connect to 192.0.2.1:5601 failed
If the TcpTestSucceeded in the Powershell results shows True, then check the esmd.log (Unix\Linux) or the esmagent.log (Windows) on the agent to see if the agent registers the connection. See the ‘How to verify that Telnet or Powershell connected to the target server’ section below.
How to verify that Telnet or Powershell connected to the target server
Just running Telnet or Powershell and connecting to a server is only part of the test. If the DNS is incorrect, or if there are firewalls between the originating server and the target server, it can seem to connect but it might not be the correct server. Checking the logs of the target server can confirm that the telnet did indeed connect to the target server is required.
Confirm connectivity by checking the CCS logs on the target server:
Response if using Telnet to test communication:
[04960] [2020/07/23 16:55:21:015] [CRITICAL] Scheduler: connection handshaking failed.
csp__server_handshake: error reading version from client
buffer is not large enough (data length = 3338, buffer size = 2064)
Response if using PowerShell to test communication:
[08704] [2023/05/09 11:05:32:685] [CRITICAL] connection handshaking failed.csp__server_handshake: error reading version from clientconnection closed by remote process
Note the date/time in the entry above on the target server, and compare that to when you ran the telnet (or PowerShell) command on the originating server. If it matches then it did connect to the target server correctly.
Log location for the CCS agents: (For checking connectivity issues from CCS manager to a CCS agent)
- Windows agent: \Program Files (x86)\Symantec\Enterprise Security Manager\ESM\system\<EXAMPLE>\esmagent.log
- UNIX/Linux agent: /esm/bin/<EXAMPLE>/esmd.log
Note about Firewalls:
[06428] [2020/07/24 17:32:40:294] [INFO] TCP server: 2020/07/24 <IP>: Connect from ##.##.#.#
