There are several reasons you might want to access your Files.com site through multiple custom domains, such as if you're supporting multiple brands with one site, handling legacy integrations that rely on an old custom domain, or to minimize downtime when switching between two custom domains. Accessing your site from multiple custom domains requires manual configuration.

Plan Ahead to Minimize Downtime

You can minimize the downtime involved in switching from a Files.com certificate to your own SSL certificate by setting your CNAME records to a low TTL before you make the switch. Ideally, the Time-To-Live (TTL) duration for your CNAME DNS records should be no more than 60 seconds.

Since you will be providing your own SSL certificate, upload your new certificate to your site prior to changing the custom domain.

When you are ready to activate your new certificate, do so immediately after changing your CNAME records. With a sufficiently low TTL, you will likely see only a few minutes of disruption before your certificate will be served for your site.

By timing the changes to minimize DNS propagation time and activating your new certificate as soon as possible after switching your CNAME records, you can minimize any disruption to just a few minutes.

SSL Certificates for Multiple Domains

In order to access Files.com from multiple custom addresses, you'll need to manage your own SSL certificate. Many SSL vendors provide a form for generating certificate signing request (CSR) for your certificate. If you wish to use Let's Encrypt for your certificate, their Certbot utility can be installed on a variety of platforms to manually generate a certificate that you can upload into your account.

You'll need to generate a CSR for and upload a certificate that uses Subject Alternative Name (SAN) that covers all of the domains you want to use. You should list the domain that will be your primary custom domain first in the certificate.

When you generate the CSR, specify all of the domains that the certificate is for. Do not use a wildcard, such as *.example.com, which is not compatible with Files.com.

If you have the option to specify the key type when generating the ticket, only RSA key types are compatible with Files.com.

You Are Responsible For Renewing Your Certificate

Because you must supply your own SSL Certificate in order to use your site with multiple domains, you are responsible for renewing the certificate. Plan to renew any expiring SSL Certificate prior to its expiration date and time.

Once your SSL Certificate Provider has provided you with your renewed SSL Certificate, import the certificate (and its intermediate certificates) just as you imported the previous one. You can activate the new certificate before the old certificate expires.

Applying and activating a renewed SSL Certificate will not change your custom domain or its dedicated IP addresses.

SAN Certificates Are Not Wildcard Certificates

You cannot use a Wildcard SSL certificate with the Custom Domain feature. Only domains which are explicitly listed in your certificate can be used as a custom domain for your Files.com site.

Custom Domain Setting

Files.com offers a setting for a single custom domain. This domain should match the first domain listed in your SSL certificate. Any links generated by the platform will use this custom domain address.

Configure Your Custom Domain

Create the CNAME records for each custom domain you will use for your site. All of the domains that will be used with your custom domain will use the same CNAME record value - an address that contains your subdomain name in the form s-[subdomain].di.app.files.com.

With your SAN certificate in hand, you can upload it as you would when configuring a single custom domain. After uploading your SSL certificate, you must activate it.

Complete the setup of your custom domain by updating your custom domain setting in Files.com with the primary domain address. You can only choose one domain to be the primary custom domain of your site. This should match the first domain listed in your SSL certificate.

Accessing Your Site By Primary Custom Domain

Once you've completed configuring your custom domain with the SAN certificate, the appropriate CNAME records and the main custom domain setting, you can access the site through the web URL that matches your custom domain setting. When you do, you should be served the certificate that includes all of the domains you wish to use.

Accessing Your Site By Secondary Custom Domain

Once you've finished setting up your custom domain, you should be able to log in via web, API, WebDAV or FTPS at the alternate domain addresses from your certificate. When you do, you'll be served the certificate that lists your primary domain as the "Common name" and your other domains in the "Alternative names".

You can also access your site through SFTP at the secondary addresses, but because SFTP does not use SSL certificates, this won't provide the certificate you configured.

Share Link and Inbox URLs

Share Links and Inboxes will use your primary custom domain address to generate links. Even if you connect through a secondary custom domain, the generated URLs will use your primary custom domain.

Emailed Links

Files.com provides multiple features that will email links to the platform. This includes Inbox and Share Link invitations, Email notifications, new user welcome emails, password recovery emails and site alert emails. Any links sent by the platform will always use the primary custom domain address; there is no way to override this behavior.

Using Child Sites for Multiple Custom Domains

Child sites offer a simple way to support multiple brands for your users by creating a separate site for each domain.

A child site is an entirely separate site that is associated with your primary account. Each child site's content and its settings, such as remote servers, logos, and custom domain are separate from all your other sites. Parent site users can be granted access to any of your child sites.

Each child site's custom domain can use a Files.com-managed SSL certificate. Branding a child site with a custom domain also means that generated URLs (such as with share links, inboxes, public hosted, or emailed links) will always match the child site's custom domain.

To share the same content across multiple sites, use copy automations within the parent site to copy data to child site folders. Another option is to add the parent site as a remote server within a child site, and then either mount a parent folder in the child or sync folders between the child and parent.