Set up email sending: domains, SPF/DKIM/DMARC, and SMTP

Why email needs setup

Anyone can type an email address, but mailbox providers (Gmail, Outlook, and others) only trust mail that is authenticated — provably sent by someone authorized to use your domain. StretchMail handles the sending infrastructure, but you have to prove you own the domain and publish a few DNS records so your mail passes authentication. Skip this and your messages land in spam or get rejected.

The three records that matter are SPF, DKIM, and DMARC. StretchMail generates the exact values; you publish them at your DNS provider.

What the records do

• SPF (a TXT record) lists which servers are allowed to send mail for your domain.
• DKIM (a TXT/CNAME record) adds a cryptographic signature so receivers can verify the message wasn't forged or altered.
• DMARC (a TXT record) tells receivers what to do with mail that fails SPF/DKIM, and where to send reports.

How to verify a sending domain

1. Open StretchMail and go to the Domains tab.
2. Click Add domain and enter your sending domain (for example paynecoaching.ca).
3. StretchMail shows you a set of DNS records to publish — the SPF, DKIM, and (recommended) DMARC records with their exact host names and values.
4. Log in to your DNS provider (your registrar or wherever your domain's nameservers live) and create each record exactly as shown — record type, host/name, and value all matter.
5. Save the records and wait for DNS to propagate (minutes to a few hours).
6. Back in StretchMail, click Verify on the domain.
7. When all records resolve, the domain flips to Verified, and it can send and receive.

Set up mailboxes and inbound routing

Once a domain is verified you can:

1. Create mailboxes (real inboxes like hello@paynecoaching.ca) and aliases (forwarding addresses).
2. Configure inbound routing so replies and inbound messages land where you want — an inbox, a forward, or into a workflow.
3. Use the domain for campaigns and transactional sending, with delivery reporting to track opens, bounces, and failures.

StretchMail manages the outbound SMTP delivery and inbound provider health for you — the Deliverability view shows outbound SMTP and inbound provider status so you can see at a glance whether sending is healthy.

A realistic example

A coaching business wants hello@paynecoaching.ca for replies and to send a monthly newsletter:

1. In StretchMail → Domains, they add paynecoaching.ca and copy the three DNS records shown.
2. At their registrar, they add the SPF TXT, the DKIM record, and a DMARC TXT record.
3. An hour later they click Verify; the domain shows Verified.
4. They create the hello@ mailbox and set inbound routing so replies land in it.
5. They send a test to a personal Gmail — it arrives in the inbox (not spam) and passes authentication.
6. They build the newsletter as a campaign and watch delivery reporting for opens and bounces.

Troubleshooting

Domain won't verify — the most common cause is a record typo or a record placed at the wrong host. Re-copy the exact values from StretchMail. Watch for your DNS provider auto-appending your domain to the host (leading to doubled names like _dmarc.paynecoaching.ca.paynecoaching.ca).

Verified but mail still goes to spam — make sure all three records exist, not just SPF. DKIM signing and a DMARC policy meaningfully improve inbox placement. Also avoid spammy content and warm up new domains gradually.

Two SPF records — a domain may only have one SPF TXT record. If you already had one (for another mail service), you must merge them into a single record, not add a second.

Changes not taking effect — DNS caches. Wait for propagation and your record's TTL before assuming failure; then re-verify.

Bounces on send — check delivery reporting; hard bounces mean bad addresses, soft bounces are temporary. Persistent inbound problems show up under Deliverability as provider health.

Tips

• Publish DMARC even at a monitoring policy (p=none) to start getting reports before enforcing.
• Use a subdomain for bulk sending (for example mail.paynecoaching.ca) to protect your main domain's reputation, if you send high volume.
• Don't send to purchased lists — it wrecks deliverability for the whole domain.

FAQ

Do I need my own SMTP server? No. StretchMail is the sending infrastructure; you just authenticate your domain via DNS.

How long does verification take? As long as DNS propagation — usually minutes, sometimes a few hours.

Can I send from a domain I don't own? No — authentication requires publishing records on that domain's DNS, which requires control of it.