Outbound Email Settings
Your site includes settings that allow you to customize how emails from Files.com are generated.
Customizing Welcome Emails
By default, new users are sent a welcome email when they are added to your site. Site administrators can change the Welcome emails setting to disable this behavior and have several other options to customize the welcome email.
Email From Address
Emails are sent with a from address to indicate the sender. To be SPF and DMARC compliant, the From address needs to be an address actually related to the sending email server.
By default, Files.com sets the From address to no-reply@files.com, because the mail is sent from a Files.com mail server. A custom SMTP server lets your site use its own sender address.
Email Reply-To Address
Site administrators can customize the Email notifications reply to address setting to indicate the address that receives replies. If this address has not been set, Files.com will use the main site contact email address as the reply-to address, except when the email is also being sent to that same address.
Some mail servers will reject any message sent to the same email address as the Reply-To address. To prevent this, Files.com will not set a Reply-To address when it would match the address the mail is being sent to.
Custom SMTP
Customers on some plans can send all outbound mail through a custom SMTP server. This lets you set the sender name and From address and use an email service with domain authentication such as DKIM and SPF.
Enabling Custom SMTP for your outbound email will remove some references to Files.com from the body of some emails. These references cannot be removed unless you use Custom SMTP, as they are required to comply with anti-spam laws such as the CAN-SPAM Act.
We recommend using an email delivery provider designed for high-volume application or SaaS email, such as Amazon SES, Twilio SendGrid, Sinch Mailgun, Azure Communication Service, Mailchimp, or Postmark. These providers also support domain authentication.
Avoid using mailbox-oriented services like Microsoft Exchange, Office 365 or Google Workspace, as they are optimized for end-user email rather than automated system messages. A dedicated email delivery service produces reliable message delivery and avoids problems with throttling, authentication limits, and mail server policy restrictions.
Microsoft Exchange Online Is Not Compatible
Files.com's Custom SMTP configuration does not offer OAuth authentication. Use a transactional SMTP service that accepts one of the authentication methods listed in SMTP Settings. Exchange Online's SMTP AUTH policies and Basic authentication retirement make it unsuitable as a long-term Custom SMTP configuration; do not assume that enabling SMTP AUTH provides OAuth support in Files.com.
For an alternative solution within the Microsoft ecosystem, Azure Communication Services can provide SMTP services for your Files.com site. You can also use other mail providers, such as Amazon SES, SendGrid, Mailgun, or Postmark.
SMTP Settings
By default, your site will use the standard outbound SMTP, which uses the Files.com email service. If you instead enable the custom outbound SMTP, you must provide the information for connecting to your email service.
Site Administrators configure these settings under Integrations > Custom SMTP or Networking > Custom SMTP. These settings apply to all Custom SMTP mail across your site's Workspaces, including notifications and messages sent by Automations.
The Server address must be the fully qualified hostname of your SMTP server. If you want to use a port other than the default of 25, enter that in the Server port.
The Authentication type refers to how you authenticate to your SMTP service. Valid options are none, plain, normal, or cram_md5. Your mail provider will tell you which option is appropriate for your service.
If you select an option besides none for the authentication type, you must also provide the SMTP username and SMTP password that will be used for sending mail. Along with the required address that messages will be sent from, you can also provide a reply-to address.
Custom SMTP connections use the Files.com general IP pool by default. If your site has default dedicated IP addresses, you can enable dedicated-IP routing through the Files.com API.
Connections then originate from the site's default dedicated addresses. Enable this option when your mail provider or firewall requires a fixed set of source addresses, so it can allow those addresses instead of the whole Files.com IP range.
SMTP Encryption
The SSL Mode dropdown controls Transport Layer Security (TLS) encryption between Files.com and your mail server. It applies to every authentication type, including none. Authentication controls how Files.com identifies itself to the server; encryption protects credentials and message contents while they travel to it. When the Custom SMTP settings row is closed, the current mode appears beneath the server name.
Choose a required mode when credentials and messages must be encrypted from the first connection. Match the mode and port to your provider's requirements: Require SSL (Explicit) uses STARTTLS, usually on port 587, while Require SSL (Implicit) starts TLS immediately, usually on port 465.
Selecting a port alone does not select an encryption mode. Whenever TLS is used, Files.com verifies the server's certificate against the configured Server address.
| SSL Mode | Connection Behavior |
|---|---|
| Use If Available (default) | Uses STARTTLS when the server offers it. Until a verified STARTTLS connection succeeds, a server that does not offer STARTTLS can receive credentials and messages unencrypted. If the TLS handshake fails, delivery fails without falling back to an unencrypted connection. |
| Require SSL (Explicit) | Requires the server to offer STARTTLS and successfully establish TLS before authentication or message delivery. Delivery fails if STARTTLS is unavailable or the TLS handshake fails. |
| Require SSL (Implicit) | Uses TLS from the start of the connection. Delivery fails if the TLS handshake fails. |
| Never Use | Disables TLS. Credentials and messages are sent unencrypted. |
With Use If Available, the first certificate-verified STARTTLS connection to your configured server automatically changes the saved SSL Mode to Require SSL (Explicit). This preserves encryption for later connections and retries once the server has demonstrated support for it. The change occurs even if authentication or message delivery subsequently fails; a delivered email is not required.
If a Child Site Management Policy controls the child site's SSL Mode, Files.com preserves that policy value. A child site's setting can change automatically when it is not controlled by a parent policy.
Files.com never automatically lowers the SSL requirement. A Site Administrator can explicitly change the mode; selecting Use If Available again restarts the same behavior on the next verified STARTTLS connection.
Switching your site to Use standard outbound SMTP server resets SSL Mode to Use If Available. If you later enable Custom SMTP again, select a required mode when encryption must be enforced from the first connection.
Automatic Retries
Files.com will automatically retry sending emails through your Custom SMTP server if the server is unavailable or not accepting mail. Retries will continue for up to 4 days.
If you update your Custom SMTP credentials or switch to a different SMTP server, Files.com will use your new settings for subsequent retry attempts. Changing the Server address or Server port does not automatically lower the SSL requirement, so the replacement server must support the selected mode.
If delivery stops after Use If Available changes to Require SSL (Explicit), confirm that your mail server still offers STARTTLS and has a valid certificate for the configured hostname. When a hostname connects to multiple mail servers, each server must support the required mode.
Losing STARTTLS support or reaching a server without it causes delivery attempts to fail; Files.com does not send credentials or messages unencrypted as a fallback. Restore the server's TLS support or configure a compatible server, and use Outbound Emails to inspect delivery failures.