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Mail Express Server Admininstration portal requires that port 443 is available for the Mail Express Server IP address

Karla Marsh
Mail Express - DEPRECATED


  • Mail Express, version 3.x and later


The Mail Express Server Administration portal requires that port 443 is available for the IP address on which Mail Express listens. To determine if the port is available to be used for the IP address for Mail Express, at a command prompt (Start > Run > cmd) type the command below. (Don't copy and paste the command as this can copy unrecognizable characters and the command will not work.)

netstat –ona | findstr "LISTEN"

Using "LISTEN" finds numerous processes. To identify only the processes that are listening on port 443 (if any), use the following command:

netstat -ano | findstr :443

  • If another application is listening to the port and IP address that you are trying to use, there will be a conflict.
  • If the wildcard IP address ( is being listened to, then there will also be a conflict.
  • This command will also show the PID (Process Identifier) for the processes. If it's not clear which process is listening on port 443, you can run TaskList against the PID found. The recommended command to use is:

tasklist /SVC /FI "PID eq <result>"

  • To get the information on the process you found, for example, 1234, then you can use the following command :

tasklist /SVC /FI "PID eq 1234"

If the PID is equal to 4 (System) then it may be that IIS is also running on the computer. By default IIS listens on all ports. IIS is “greedy” on listening to IP address; even when IIS Manager sets a specific IP address, HTTP.SYS will still listen on “all incoming” (referred to as “socket pooling”). To install Mail Express and IIS on the same computer, identify the version of IIS in use and disable this behavior.

For more information on the TaskList command, refer to the Microsoft Technet article at

Last Modified: 13 Years Ago
Last Modified By: GlobalSCAPE 5
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