How Can Users Find the IP Address of an SMTP Server?

In the Windows operating system, users can find the IP address of an SMTP server by using the “ping” command and the server’s hostname in the command prompt. The same process is used in the terminal of Unix-based systems such as Linux and Mac OSX.

SMTP, or the Simple Mail Transfer Protocol, is the communications protocol used by mail servers to send email. Many email programs, such as Microsoft Outlook or Mozilla Thunderbird, use a mail server’s hostname to send email through it. This is often in the form “” or “” However, sometimes it is necessary to specify the server’s IP address instead. This is easy to find in all operating systems as long as users know the mail server’s hostname. If they do not, they should contact their Internet service provider or email service provider for the details.

Procedure in Windows

  • Click on the “Start” button and type “command prompt” or “cmd”
  • Click on the icon for the “Command Prompt” program
  • At the prompt, type “ping” followed by a space and the mail server’s hostname. For example, “ping”.
  • Press the “Enter” key

The command will generate the following line a few lines before returning users to the prompt: “Pinging [a.b.c.d] with 32 bytes of data.” The sequence in square brackets, [a.b.c.d], is the IP address of the SMTP server.

Users can use the same command in the terminal found in all Unix systems, including Mac OSX, to find the IP address of SMTP servers.