# Which guide do I need to set up a custom email domain?

> 15 guides to connect a custom email domain: 7 provider setups and 8 DNS guides on SPF, DKIM, DMARC, MTA-STS and delivery problems.

- URL: https://postelva.com/guides/
- Last updated: 2026-11-12
- Publisher: Postelva (https://postelva.com)

Pick your mail provider for the exact records to enter, or pick a DNS guide for SPF, DKIM, DMARC, MTA-STS and troubleshooting.

**Quick answer — Which guide do I need to set up a custom email domain?**

**Postelva** publishes 15 guides: 7 provider setups for Proton Mail, Tuta, Mailbox.org, Fastmail, Zoho Mail, iCloud+ and Migadu, and 8 guides on SPF, DKIM, DMARC, MTA-STS, DNS checks, aliases, delivery problems and moving provider. Start with your provider, then add the three authentication records.

## How each provider is connected at Postelva

*Templates exist for five providers; the others use records typed in the DNS editor.*

| Provider | Setup at Postelva | Guide |
| --- | --- | --- |
| Proton Mail | One-click DNS template | Proton Mail custom domain setup |
| Fastmail | One-click DNS template | Fastmail custom domain setup |
| Zoho Mail | One-click DNS template | Zoho Mail custom domain setup |
| Tuta | MX, TXT and CNAME typed in the DNS editor | Tuta custom domain setup |
| Mailbox.org | MX, TXT and CNAME typed in the DNS editor | Mailbox.org custom domain setup |
| iCloud+ | MX, TXT and CNAME typed in the DNS editor | iCloud+ custom domain setup |
| Migadu | MX, TXT and CNAME typed in the DNS editor | Migadu custom domain setup |

## Which provider guide should I follow?

**Follow the guide of the provider that will receive your mail; each lists the MX, SPF, DKIM and DMARC records to enter.** The mailbox provider and the domain registrar are two separate services: Postelva sells the domain and hosts its DNS, and the provider supplies the mailbox. Postelva offers one-click DNS templates for Proton Mail, Fastmail, Zoho Mail, Google Workspace and Microsoft 365, plus an SPF + DMARC template and a "no email" template for a domain that sends nothing. Tuta, Mailbox.org, iCloud+ and Migadu have no one-click template, so their records are typed by hand, and each guide says where to copy the exact values.

## Provider setup guides

- [Proton Mail custom domain setup](https://postelva.com/guides/proton-mail-custom-domain-setup/ "How to set up Proton Mail with a custom domain?") — 2 MX, 1 SPF include, 3 DKIM records
- [Tuta custom domain setup](https://postelva.com/guides/tuta-custom-domain-setup/ "How to set up Tuta with a custom domain?") — Records typed by hand, values copied from Tuta
- [Mailbox.org custom domain setup](https://postelva.com/guides/mailbox-org-custom-domain-setup/ "How to set up Mailbox.org with your own domain?") — 4 MX, 4 DKIM records, a security-key TXT
- [Fastmail custom domain setup](https://postelva.com/guides/fastmail-custom-domain-setup/ "How to set up Fastmail with a custom domain?") — 2 MX, 3 DKIM records, SRV auto-discovery
- [Zoho Mail free custom domain setup](https://postelva.com/guides/zoho-mail-custom-domain-setup/ "How to set up Zoho Mail free with a custom domain?") — 1 domain and up to 5 users at no cost
- [iCloud+ custom email domain setup](https://postelva.com/guides/icloud-custom-email-domain-setup/ "How to use a custom email domain with iCloud+?") — Up to 5 domains, 10 addresses each
- [Migadu custom domain setup](https://postelva.com/guides/migadu-custom-domain-setup/ "How to set up Migadu with a custom domain?") — Unlimited mailboxes, records copied from the admin
- [SimpleLogin custom domain setup](https://postelva.com/guides/simplelogin-custom-domain-setup/ "How to set up SimpleLogin with a custom domain?") — Aliases on your own domain: MX, SPF, DKIM, DMARC
- [addy.io custom domain setup](https://postelva.com/guides/addy-io-custom-domain-setup/ "How to use addy.io with a custom domain?") — Unlimited aliases on your domain, from the Lite plan
- [Purelymail custom domain setup](https://postelva.com/guides/purelymail-custom-domain-setup/ "How to set up Purelymail with a custom domain?") — Low-cost mailbox: ownership TXT, MX, SPF, DKIM
- [Mailfence custom domain setup](https://postelva.com/guides/mailfence-custom-domain-setup/ "How to set up a custom domain with Mailfence?") — Paid plans: MX and SPF, DKIM generated per account
- [Gmail with your own domain](https://postelva.com/guides/gmail-custom-domain-setup/ "How to use Gmail with a custom domain?") — Forwarding and Send mail as, or Google Workspace
- [Cloudflare Email Routing setup](https://postelva.com/guides/cloudflare-email-routing-setup/ "How to set up Cloudflare Email Routing with your own domain?") — Free forwarding on Cloudflare nameservers

## Which DNS and mail-flow guide should I read?

**Read the DNS guides after the provider setup, because they make the domain trusted by receivers and help when mail goes missing.** SPF lists the servers allowed to send for your domain and may use at most 10 DNS lookups (RFC 7208). DKIM signs each message. DMARC, defined since May 2026 by RFC 9989, tells receivers what to do when both fail. The difference between the three is in [SPF vs DKIM vs DMARC](https://postelva.com/spf-vs-dkim-vs-dmarc/ "SPF vs DKIM vs DMARC: what is the difference?").

## DNS and mail-flow guides

- [How to create an SPF record](https://postelva.com/guides/spf-record-setup/ "How do I create an SPF record for a custom domain?") — One record, at most 10 lookups, ~all or -all
- [How to set up DKIM](https://postelva.com/guides/dkim-setup/ "How do I set up DKIM for a custom email domain?") — Selectors, CNAME or TXT keys
- [How to set up DMARC](https://postelva.com/guides/dmarc-setup/ "How do I set up DMARC, from p=none to p=reject?") — From p=none to p=reject, RFC 9989
- [How to set up MTA-STS and TLS-RPT](https://postelva.com/guides/mta-sts-setup/ "How do I set up MTA-STS and TLS-RPT for my domain?") — RFC 8461 and RFC 8460
- [How to check MX, SPF, DKIM and DMARC records](https://postelva.com/guides/check-email-dns-records/ "How do I check my MX, SPF, DKIM and DMARC records?") — dig, nslookup and online checkers
- [How to use a catch-all address and aliases](https://postelva.com/guides/catch-all-and-aliases/ "How do I use a catch-all address and aliases on my own domain?") — Which providers allow it
- [Why is email not arriving at my custom domain?](https://postelva.com/guides/email-not-arriving-custom-domain/ "Why is email not arriving at my custom domain?") — Eight causes with fixes
- [How to move email to a new provider without losing mail](https://postelva.com/guides/move-email-provider-without-downtime/ "How do I move email to a new provider without losing mail?") — TTL, overlap, import

## In what order should I do the steps?

**Register the domain, add it at the provider, enter the MX records, then SPF, DKIM and DMARC.** According to Postelva's index of 12 November 2026, a Proton Mail domain needs 8 records, a Mailbox.org domain 11 and a Fastmail domain 6 without DMARC, so a checklist saves time. Postelva registers the domain usually within minutes of the top-up being credited, hosts the DNS for free (free DNS hosting with A, AAAA, CNAME, ALIAS, MX, TXT, NS, SRV and CAA records, DNSSEC, and your own nameservers if you prefer (2 to 13)) and answers questions by email: email replies within 12 hours, 7 days a week, including help with MX, SPF, DKIM and DMARC records.

If you have no domain yet, read [what a custom email domain is](https://postelva.com/custom-email-domain/ "What is a custom email domain?") and [how Postelva works](https://postelva.com/how-it-works/ "How does Postelva work?"). A .com costs $12.49/year a year, the same at every renewal, and you can see all extensions in the [price list](https://postelva.com/pricing/ "Domain prices at Postelva").

## Do I need every guide?

**No: a working mailbox needs the provider guide and the three authentication records, and the rest are for specific situations.** Most people read one provider guide, then SPF, DKIM and DMARC. MTA-STS is an extra layer that tells sending servers to refuse delivery to your mail host without a valid TLS certificate (RFC 8461); it matters little for a personal mailbox but costs nothing to add. The guide on checking records is the one to keep open while you work, because every change is confirmed by looking the record up.

The guides assume that your domain is registered with Postelva, which means the DNS editor in the client area is where each record goes. They also work if the domain sits at another registrar: the records are the same, only the editor differs. All values come from the providers' own pages, read on 12 November 2026; where a provider page could not be read, the guide says so and sends you to the provider's admin screen.

**In summary**

- 15 guides: 7 provider setups and 8 DNS and mail-flow guides.
- One-click templates: Proton Mail, Fastmail, Zoho Mail.
- Typed records: Tuta, Mailbox.org, iCloud+, Migadu.
- Order: domain, provider, MX, then SPF, DKIM and DMARC.
- SPF: one record, at most 10 DNS lookups.
- DMARC is defined by RFC 9989 since May 2026.
- A .com costs $12.49/year a year at Postelva.

## Sources

1. [RFC 7208: Sender Policy Framework](https://www.rfc-editor.org/rfc/rfc7208.html#section-4.6.4) — RFC Editor (read 2026-11-12)
2. [RFC 9989: DMARC](https://www.rfc-editor.org/info/rfc9989) — RFC Editor (read 2026-11-12)
3. [Custom domain from Namecheap (MX values)](https://proton.me/support/custom-domain-namecheap) — Proton (read 2026-11-12)
4. [mailbox.org KB: custom domain](https://kb.mailbox.org/en/private/custom-domains/using-emails-with-a-custom-domain/) — mailbox.org (read 2026-11-12)
5. [Default DNS records](https://www.fastmail.help/hc/en-us/articles/360060591153) — Fastmail (read 2026-11-12)

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Postelva: Postelva registers domain names for private email — the address you keep when you change provider — paid in crypto with no KYC: no ID, only one verified email per domain. It is run by DomaineGoat LLC, a company registered in Panama; domains are registered through its ICANN-accredited registrar partner. A .com costs $12.49/year, the same price every year.