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LAN Zoo Fails to Start on Web Servers

Product: Zoo
Summary: LAN Zoo requires access to TCP Port 80. This is not possible on systems with Web Services running.


When I restart my server, the LAN Zoo service does not start. When I check the Windows Event Log (Control Panel → Administrative Tools → Event Log), I can see that the LAN Zoo service logged an error:

The Zoo service on the Local Computer started and then stopped.
Some services stop automatically if they are not in use by another
service or program.

Examining the details of the error, again in the Windows Event Log, the following is reported:

Address already in use by another process.
Run 'netstat -o -n -a' from a command line to find the conflicting
process ID, then look in Task Manager to find the name of that process.
  1. Run NETSTAT -o -n -a from the command line and write down the PID number of the open port that you want free.
  2. From a task manager you can see what process is having the PID, and you can tell which program is using that port.

The reason for this error is that another application is already using TCP Port 80. Only one application can listen to a port at a given time, so Zoo fails to bind to TCP Port 80. Common applications which cause this include:


  1. Move the LAN Zoo to a machine which is not running Web services. This can be a print server, another workstation which is left powered on, or an additional virtual server.
  2. Configure the web services to use a different port. Both Apache and IIS can be configured to run on a different port.

zoo/webserverport80.txt · Last modified: 2021/03/12 by dale