From MozillaZine Knowledge Base

You can set up Thunderbird to use more than one SMTP (outgoing) server, or to use the same server with different usernames and passwords, so that each of your mail identities can have its own SMTP server configuration.

Basic setup

To add an additional SMTP server:

• Go to account settings.
• At the bottom of the left pane (you may need to scroll down), click on "Outgoing Server (SMTP)".
• Click the "Add..." button.
• Insert the SMTP server information that you want, and click the "OK" button.

To use this newly added SMTP server for an account's default identity:

• In account settings, in the left pane, click on the account name whose default identity you want to change.
• At the bottom of the "Default Identity" panel, choose the SMTP server you want to use from the "Outgoing Server (SMTP)" pulldown list.

To use this newly added SMTP server for any other identity:

• In account settings, in the left pane, click on the account name whose identities you want to change.
• Press the Manage Identities... button.
• Select the identity that you want to change, and press the Edit... button.
• Choose the SMTP server you want to use from the "Outgoing Server (SMTP)" pulldown list.

Note:  When you press the Manage Identities... button and change settings there for the default identity, bug 373573 can prevent the Outgoing Server (SMTP) setting from transferring back to the main Account Settings page. To work around this, use the main Account Settings page to change this setting.

Useful extensions

If you have set up multiple SMTP servers and periodically need to change the default SMTP server (perhaps you have a laptop computer that you use on different networks depending upon whether you're at home or work), you could add a button to the toolbar to select the SMTP server using the SmtpSelect extension or the Buttons! extension. You need to right click on the toolbar, drag and drop the button to the toolbar, and then press the OK button to do this.

Troubleshooting

If you have set up a new SMTP server, associated it with one or more of your mail identities, and find that you cannot send mail with it, try going through the points listed on this page.

See also

• SMTP authentication
• POP before SMTP support
• Multiple identities per e-mail account
• Mail concepts