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

For Thunderbird 1.5 or later

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.

For Thunderbird 1.0.x

To add an additional SMTP server:

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

To use this newly added SMTP server for any of your mail accounts:

• Go to "Tools -> Account Settings", and then in the left pane click on "Server Settings" for the account whose SMTP server you want to change.
• Click on the "Advanced" button.
• In the dialog box that pops up, click on the "SMTP" tab, then select the SMTP server that you want to use and click the "OK" button.

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.

For version 1.0.x only: Some people have experienced a possible bug with multiple SMTP servers ([1]). Even though the settings appear to be right (as shown in "Tools -> Account Settings -> Outgoing Server (SMTP)"), in some installations Thunderbird may always use the topmost server for sending e-mails. This can be fixed by removing all other SMTP servers (via the "Advanced" button). Another solution is to change the account settings for the account that you want multiple outgoing servers for so that the SMTP server is "Always use default server". You can get to this setting through "Tools -> Account Settings -> [account name] Server Settings -> Advanced [button] -> SMTP [tab]", and then selecting "Always use default server". After this procedure, that account will always use whichever SMTP server is set as default, not necessarily the one at the top of the SMTP server list. (Note: This bug is fixed since 2005-04-07; the fix will be included in Thunderbird version 1.5.)

See also

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