Telnet is a useful utility to check if a server port is listening, and thus, if a server has started correctly. By default, Windows does not install the telnet.exe program.
Open a command window and enter telnet; if telnet is installed, you will get a prompt that looks something like this:
Welcome to Microsoft Telnet Client Escape Character is 'CTRL+]' Microsoft Telnet>
To exit this telnet prompt, just type quit.
If telnet is not installed, you will get the following error message:
telnet is not recognized as an internal or external command, operable program or batch file.
To install the telnet executable:
To see if Talend Administration Center (TAC) is running on your local machine on port 8080, type:
C:\Users\jsmith> telnet localhost 8080
or to see if TAC is running on a machine called mytac.mycorp.com on port 9090:
C:\Users\jsmith> telnet mytac.mycorp.com 9090
or to see if the MySQL server is running on a machine called mysql.mycorp.com on its default port, 3306:
C:\Users\jsmith> telnet mysql.mycorp.com 3306
If each of these servers is running, you should get a blank/black screen.
You can exit quickly by holding down the CTRL+D (end input) keyboard combination. If this does not work, you may need to quit/close the entire CMD window.
If you attempt to connect to a server and port where a server is not listening, you will get some type of Connect failed message, and end up back at the command prompt:
C:\Users\jsmith> telnet localhost 9393 Connecting to localhost...Could not open connection to the host, on port 9393: Connect failed C:\Users\jsmith>
The -I switch for curl says to only print the response headers, not the full text of the page:
C:\Users\jsmith>curl -I "http://localhost:8080" HTTP/1.1 200 OK Server: Apache-Coyote/1.1 Content-Type: text/html;charset=UTF-8 Transfer-Encoding: chunked Date: Thu, 19 Apr 2018 23:03:14 GMT
If your server is not started properly, you will get an error message, for example:
C:\Users\jsmith>curl -I "http://localhost:8080" curl: (7) Failed to connect to localhost port 8080: Connection refused
The wget command does not have as much normal output, so you do not need switches:
C:\Users\jsmith>wget "http://localhost:8080" --15:59:56-- http://localhost:8080/ => `index.html.17' Resolving localhost... done. Connecting to localhost[127.0.0.1]:8080... connected. HTTP request sent, awaiting response... 200 OK Length: unspecified [text/html] [ <=> ] 11,432 10.90M/s 15:59:56 (10.90 MB/s) - `index.html.17' saved 
Of course, the full URL of your TAC will be something like:
or, if you like to use a shorter name for your TAC: