SMTP

An email client set up to download incoming email via POP or IMAP also needs to be configured for SMTP (Simple Mail Transfer Protocol) to send outgoing messages via the Runbox servers.

SMTP configuration for regular Runbox accounts

In your email client, make sure your Runbox account is set up to use authentication when connecting to the outgoing SMTP server. The following information is required:

• Outgoing SMTP server: smtp.runbox.com
• Port: 26, 465 and 587 (port 25 is available but not recommended due to very requent blocking by ISP's, firewalls etc)
• Username: Your Runbox username (the first part of your username@runbox.com email address)
• Password: Your Runbox password

Note for some mobile device users: You may need to specify a non-default port on the following format: smtp.runbox.com:465

If you experience connection problems, please see the Connection Problems page.

SMTP configuration for hosted domains

When hosting your email domain with Runbox, you must provide the SMTP server with the username and domain for your account.

If you have a Runbox account with an address on the format username@yourdomain.com, use username%yourdomain.com as the login username in your SMTP configuration (note the percent (%) sign).

Secure (encrypted) SMTP configuration

To connect securely to runbox' SMTP server, use the following modifications of the settings above:

• Outgoing SMTP server: secure.runbox.com
• Use secure connection: Check the option in your client for "TLS", "STARTTLS", or "Use secure connection"
• Port: 26, 465 and 587 (port 25 is available but not recommended due to very requent blocking by ISP's, firewalls etc)

Note for Microsoft Outlook (Express) users: Some versions of Outlook and Outlook Express will only support the newer TLS form of secure/encrypted SMTP on port 25. All other ports will automatically use SSL which is not supported by the Runbox SMTP server. If your Outlook SMTP connection works on 26 or 587 without SSL but not with SSL then this is probably the reason.

Note for Thunderbird users: Use the STARTTLS setting, not SSL/TLS, for encrypted SMTP connections.

Using external From addresses

Initially you are only allowed to send from addresses that are recognized by the Runbox system, such as addresses among your Runbox aliases, virtual domain addresses, etc. External addresses must be explicitly validated via the address in question to be used as a From address in an email client.

To validate an external address, enter it in the Webmail Preferences for any Webmail folder and click [Save settings]. A confirmation message will be sent to the address, requiring you to click a link in the message to confirm that you own the address. Once validation is complete you can send from that address via Webmail or SMTP.