Sending domains authenticate the emails you send so mailbox providers trust them. Under Setup → Sending Domains you add a domain, then configure its DNS records for DKIM signing, a custom tracking domain, and bounce handling. Each domain shows DKIM and tracking verification statuses (Off, Pending, Passed, Failed) plus an overall status such as Active, Pending Authentication, or Authentication Failed.
Setup is a two-step flow. If ownership verification is enabled in application settings, you first prove you own the domain — either by adding a TXT record to DNS or by uploading a verification HTML file to the domain root. You then land on the DNS authentication page, where DKIM keys are generated automatically. Enable Sign Outgoing Emails and add the displayed TXT record; enable the tracking domain and choose a redirection type — CNAME (simplest), .htaccess (Apache rewrite, hides Mumara's IP), or Index/Cloak (a PHP file, needs allow_url_fopen). If bounce processing is on, you also add SPF (e.g. v=spf1 include:spf.mumara.com ~all) and MX records for the bounce subdomain.
Worth knowing: in every DNS table the bold part of the Host is what you enter in your DNS zone — click it to copy; the Current Value column fetches live DNS automatically, and propagation can take up to 48 hours, so use Recheck after adding records. "Use Secure URL" requires a valid SSL certificate on the tracking domain, and deleting a domain in use prompts you to reassign its lists and sending nodes first.
