Custom Subdomain

Every site includes a unique custom subdomain of the domain, and site administrators can change this subdomain at any time.

Your site's custom subdomain is not impacted by your site's custom domain. Adding, changing or removing a custom domain for your site does not prevent you from using your site's custom subdomain.

Custom Domain Versus Custom Subdomain

There are several differences between your site's custom subdomain and a custom domain.

The custom subdomain for your site is a unique subdomain of the domain, in the form of <your-subdomain> - it will always end in "". A custom domain is an address that you define on any domain that you control.

Every site has its own unique custom subdomain. Configuring a custom domain is optional (and easy), and many sites do not have a custom domain. always manages the SSL certificates for your custom subdomain address. can also provide and manage SSL certificates for a custom domain address, but you have the option of providing your own SSL certificates for the custom domain. manages the CNAME DNS records for your custom subdomain address, but you are responsible for the CNAME DNS records for a custom domain.

Changing Your Subdomain if You Also Have a Custom Domain

A custom domain is tied to your site's custom subdomain via the DNS records used to link your custom domain. If you want to change your custom subdomain, you should expect downtime due to the DNS propagation needed to effect the change, and you will also need to make changes to your custom domain's DNS records to reflect the change.

This downtime is caused by 3 things: re-registering your SSL certificate (if we are registering it), a time delay where some of our edge servers will serve your old subdomain's certificate and others will serve your new subdomain's certificate, and the need to create DNS records in the DNS for your new subdomain.

We recommend you plan the switch for a time period where your site has minimal usage, such as a night or weekend.

If you are planning on changing both your custom subdomain and domain, we recommend doing these events on separate days to reduce the risks and make rollback easier.

Before You Switch Your Subdomain

To minimize downtime, plan ahead and review the steps making the change, which are: lower the TTL values on your DNS records, wait for propagation, change your subdomain, update the DNS values to point at the new subdomain, wait for the changes to take effect.

Update the Time To Live (TTL) values on the existing DNS records for your custom domain to a low value, such as 60 seconds. This will tell DNS servers across the internet to prepare for a change in the destination of this domain. This step needs to be performed ahead of time, ideally 2-3 days ahead of time, to allow the maximum impact.

Switching Your Subdomain

When ready to switch, update your subdomain setting in Then update the DNS records for your custom domain to use your new subdomain in the CNAME part of the record.

Wait for the changes to take effect.

While you could choose to increase your TTL values from 60 seconds at this point, we strongly recommend setting the value as low as your provider will allow.

If you are using dedicated IP addresses, you'll need to complete the process and update your DNS entries within 5 days to keep the same dedicated IP addresses. If the DNS entries for your custom domain are not set up properly within that 5-day period, your dedicated IPs will be released to be used by other customers.

Changing Your Subdomain if You Do Not Have a Custom Domain

You can change your custom subdomain, which will change the URLs used to access your site. When you change your custom subdomain, you will be logged out and returned to the new subdomain login page to log in again.

Your users should start using the new subdomain URL for all connections to your site immediately because the old subdomain will no longer point to your site.

When the custom subdomain is changed, any existing Share Links, Inboxes, and Publicly Hosted folders will now use your new subdomain in their link URLs. Existing links will not work, as they will have the old subdomain in them.

Email notifications that were sent prior to the change will contain outdated links. You will need to inform recipients that old links will no longer work. New email notifications will contain updated links that use your new custom subdomain.

If you have embedded your old subdomain URL into any scripts, programs, or system configurations, then you'll also need to update those to point to your new subdomain. This includes any use of our SDKs or APIs.

Changing Your Subdomain with Active SSO Integrations

Changing your subdomain does not impact or cause downtime for your Single Sign-On (SSO) integrations. No changes are required on your IdP side unless you've entered a value for the optional Relay Status URL field, which should be updated to match your new subdomain.

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