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Sending e-mail through different internet providers

Use the new Message Submission Port 587 to send mail if you have a GRU.Net account but use a different internet service provider than GRU.Net.

To help restrict "spam," "worms," etc., many Internet Service Providers (ISPs) require that all outbound e-mail use the "default" SMTP port 25. This creates problems for mobile/laptop computer users who frequently connect to different networks that require changes to their e-mail program.

GRU.Net now supports an alternative means of e-mail submission: the Message Submission Port, port number 587. It is designed to be the entry point for new messages and requires "secure authentication" using TLS. The Message Submission Port does not accept messages from unauthenticated sources helping to protect networks and users from unwanted e-mail.

Once your email program is configured to use the Message Submission Port for outbound mail you will be prompted for your username and password the first time you send a message. The system will remember your credentials after you authenticate as long as you don't exit/quit the program.

The Message Submission Port Essential Facts

GRU.Net Outgoing E-mail Host
Message Submission Port 587
Authentication Required? Yes, Username and Password
Connection Encryption TLS (note; SSL is not TLS)

This article describes how to configure two common e-mail programs to use the Message Submission Port. Other e-mail programs will generally be similarly configurable.

Configure Outlook Express

  • From the main Outlook Express menubar, select Tools
  • From the Tools dropdown menu, select Accounts...
  • On the Internet Accounts panel, select the Mail tab
  • Highlight the entry for your email account.
  • Click the Properties button
  • In the your e-mail accountname Properties dialog box, Click the Servers tab
  • In the Outgoing Mail Server section, Click the "My server requires authentication" checkbox
  • Click the Settings... button
  • Click the Log on using radiobutton
  • Make sure your username (for the server you use to send mail) is entered In the Account name: field
  • Click the OK button
  • You will be back On the main your e-mail accountname Properties dialog box. Click the Advanced tab
  • Set the Outgoing Mail (SMTP): field to 587. SSL is optional, if you wish to use SSL, Click This server requires secure connection (SSL).
  • Click the Apply button
  • Click the OK button
  • Click the Close button
  • If you are using SSL, you must accept the certificate when asked.

Configure Thunderbird

  • From the Thunderbird main menu, select Tools
  • From the Tools dropdown menu select Account Settings...
  • In the Account Settings dialog box, From the left-hand pane, select "Outgoing Server (SMTP)". You may have to scroll down in this panel to find this selection, depending on how many accounts you have configured.
  • The Outgoing Server (SMTP) Settings dialog box is shown below.
  • Enter your preferred outgoing mail server In the Server Name:
  • Enter "587" as the Port number.
  • Check the "Use name and password" checkbox
  • Enter your username for this server In the User Name: field.
  • Check the TLS radiobutton. SSL is optional, if you would prefer to use SSL, check the SSL radiobutton instead.
  • Click OK.
  • If you are using SSL, you must accept the certificate when asked.

For Further Assistance

If you need additional assistance in configuring your e-mail program, please contact the Help Desk at 352-334-3100 or

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