For troubleshooting purposes, it may be necessary to check if a port is already in use by a different application on your servers.

Checking port usage from Windows

To check the listening ports and applications with Netstat:

1. Open a command prompt. For more information, see Opening a command or shell prompt (1003892).
2. Run this command:
   
   netstat -bano
   
   You see output similar to:
   
   C:\netstat -bano | more

Proto Local Address Foreign Address State PID
TCP 0.0.0.0:port 0.0.0.0:0 LISTENING process ID
[process.exe]
TCP 0.0.0.0:port 0.0.0.0:0 LISTENING process ID
[process.exe]
...
   
   where:
    
   • process is the name of the application
   • port is the port that is being used
   • process ID is the process ID of the process
      
3. If you see Can not obtain ownership information instead of the [process.exe] entry, you can find more information in the Windows Task Manager using the process ID:
    
   • Start Task Manager by pressing Ctrl+Shift+Esc
   • Click on the Processes tab and click View then Select Columns...
   • In the Select Process Page Columns window, click PID (Process Identifier), then click OK
   • You can then sort based on the PID column and find the PID number returned from the previous command

The output shows the processes that are listening, as well as the name of the process and process ID. When reviewing the information, only look at the ports that are listening to ensure that you find the correct application that is listening on that port. If you do not see any process listening for a port, that port is free to be utilized.

When you determine what is listening on the port, you must decide what action needs to be taken to resolve the conflict. This involves stopping a service or uninstalling the application that is utilizing the port.

For a list of ports used by VMware products, see TCP and UDP Ports required to access VMware vCenter Server, VMware ESXi and ESX hosts, and other network components (1012382).

Checking port usage from Linux / Mac OS / ESX

Note: Mac OS and certain distributions of Linux do not support listing the process name with Netstat. If you are using Mac OS or are seeing errors on your distribution of Linux, follow the lsof instructions below.

To check the listening ports and applications with Netstat:

1. Open a shell prompt. For more information, see Opening a command or shell prompt (1003892).
2. In the shell prompt window, run this command:
   
   netstat -pan
   
   You see output similar to:
   
   [root@server]# netstat -pan

Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp 0 0 0.0.0.0:port 0.0.0.0:* LISTEN process ID/process
tcp 0 0 0.0.0.0:port 0.0.0.0:* LISTEN process ID/process
...
   
   where:
    
   • process is the name of the application
   • port is the port that is being used
   • process ID is the process ID of the process

To check the listening ports and applications with lsof:

1. Open a shell prompt. For more information, see Opening a command or shell prompt (1003892).
2. In the shell prompt window, run this command:
   
   lsof -i -P -n
   
   You see output similar to:
   
   [root@server]# lsof -i -P -n
COMMAND PID USER FD TYPE DEVICE SIZE NODE NAME
process process ID root 3u IPv4 3011 TCP *:port (LISTEN)
process process ID root 3u IPv4 3011 TCP *:port (LISTEN)
...
   
   where:
    
   • process is the name of the application
   • port is the port that is being used
   • process ID is the process ID of the process

The output from either of these two commands shows the processes that are listening, the name of the process, and the process ID. When reviewing the information it is important to only look at the ports that are listening to ensure that you find the correct application that is listening on that port. If you do not see any process listening for a port, than this means that it is free to be utilized.

When you determine what is listening on the port, you must decide what action needs to be taken to resolve the conflict. This involves stopping a service or uninstalling the application that is utilizing the port.

For a list of ports used by VMware products, see TCP and UDP Ports required to access VMware vCenter Server, VMware ESXi and ESX hosts, and other network components (1012382).