Support > Knowledge Base
Knowledge Base

Search the Knowledge Base: |
Search the Knowledge Base: |
Testing port connectivity with the Telnet command
Purpose
Resolution
Testing port connectivity with Telnet from Windows
To initiate a Telnet test to a port from Windows:
-
Open a command prompt. For more information, see Opening a command or shell prompt (1003892).
-
In the command prompt window type telnet <server> <port> , where <server> is the hostname or IP address of the server, and <port> is the port that you want to connect to.
-
Press Enter.
Note: To exit out of the Telnet application type Ctrl + ] and then type quit .
Depending on the application that uses the port, you may only see a blank screen with a cursor in the corner, this is normal. Two common outputs of a successful connection attempt are:
-
Connecting to port 902 on an ESX Server:
C:\>telnet server 902
Connecting...
220 VMware Authentication Daemon Version 1.10: SSL Required, ServerDaemonProtocol:SOAP, MKSDisplayProtocol:VNC
-
Connecting to port 25 on a mail server:
C:\>telnet server 25
Connecting...
220 server ESMTP Sendmail 8.13.3/8.13.3;
If Telnet is unable to connect to the port, the output is similar to the following:
C:\>telnet server 902
Connecting To server...
Connecting To server...
Could not open connection to the host, on port 902: Connect failed
C:\>
Testing port connectivity with Telnet from Linux or MacOS
To initiate a Telnet test to a port from Linux or MacOS:
-
Open a shell prompt. For more information, see Opening a command or shell prompt (1003892).
-
In the shell prompt window type telnet <server> <port> , where <server> is the hostname or IP address of the server, and <port> is the port that you want to connect to.
-
Press Enter.
Note: To exit out of the Telnet application type CTRL + ] and then type quit.
Depending on the application that uses the port, you may only see a blank screen with a cursor in the corner, this is normal. Two common outputs of a successful connection attempt are:
-
Connecting to port 902 on an ESX Server:
[root@server]$ telnet server 902
Trying server...
Connected to server.
Escape character is '^]'.
220 VMware Authentication Daemon Version 1.10: SSL Required, ServerDaemonProtocol:SOAP, MKSDisplayProtocol:VNC
-
Connecting to port 25 on a mail server:
[root@server]$ telnet server 25
Trying server...
Connected to server.
Escape character is '^]'.
220 server ESMTP Sendmail 8.13.3/8.13.3;
If Telnet is unable to connect to the port, the output is similar to the following:
[root@server]$ telnet server 902
Trying server...
telnet: connect to address server: Connection refused
telnet: connect to address server: Connection refused
Note: Several distributions of Linux do not have a Telnet client installed by default, refer to the website of your distribution for details on whether one is available and how to install the package.
Feedback
Actions
- KB Article: 1003487
- Updated: Aug 14, 2009
- Products:
VMware ACE
VMware ESX
VMware Fusion
VMware GSX Server
VMware Player
VMware Server
VMware VirtualCenter
VMware Workstation
VMware vCenter Lab Manager

