IP address or Port conflict, Cannot start Site


  • EFT Server (all versions)


IP address or Port conflicts


A Site is similar to a virtual FTP server bound to one or more IP addresses. The default port for FTP sites is 21, but you can select any number between 1 and 65,535. (Assigning a port number under 1024 (other than 21) may lead to conflicts with other programs running on your computer.) For example, if you already have another FTP server running on a particular IP address and port, and then configure EFT to listen to the same IP and port, an error message appears similar to "You have already configured the site "n" to use this IP address and port. These sites won't run at the same time."

You cannot run more than one Site at the same time with the same IP address:port. Each Site requires an IP address and port combination that is not already claimed by another process or Site. To avoid conflicts, when the same protocol is used, each Site requires a unique IP address and port, or the same IP address, but different ports. For example, because IIS typically uses port 80, you could use port 8080 for HTTP instead of 80, or 2121 for FTP instead of 21. You cannot have two Sites trying to use the same port on the same IP address. The two Sites will conflict; the Site that starts first claims the contested port. The hardware in the EFT computer does not limit the number of Sites you can set up, at least regarding how many NICs (Network Interface Cards) you have. In Windows, you can assign any number of IP addresses to a single NIC.

When two Sites are both assigned to the same IP address:port, you will have a port conflict. Only one Site will be able to run at a time.

  • For more information about defining connections to the server, refer to "Defining Connections to the Server" in the help for your version of EFT.
  • If you have Microsoft Internet Information Services on your computer, see the topic "Unable to create socket on port 21" for instructions for resolving IP conflicts with EFT.