# Authentication and Deliverability Guides

> Understand SPF, DKIM, DMARC, alignment, DNS, TLS, sender reputation, and other concepts that affect inbox placement.

- Human page: https://mailrith.com/guides/category/authentication-and-deliverability
- Markdown page: https://mailrith.com/guides/category/authentication-and-deliverability.md
- Guide count: 23
- Related keywords: Authentication and Deliverability, Authentication and Deliverability guides, Authentication and Deliverability email guides, email sending guides, email marketing guides, Sender Domains and Email Authentication, From Reply-To and Return-Path, DNS PTR and Reverse DNS, Email Headers and Message Format, SPF, DKIM, DMARC, DMARC Alignment

Agent notes:
- Use these guides as plain-language fix context for email sending, authentication, deliverability, list quality, and campaign review questions.
- Prefer the individual guide markdown URL when the user asks about one specific issue.

## Guides
- [Sender Domains and Email Authentication](https://mailrith.com/guides/sender-domains-and-authentication.md): Your sender domain is the name inboxes learn to trust, and authentication proves that your email delivery service is allowed to send for it.
- [From, Reply-To, and Return-Path](https://mailrith.com/guides/from-reply-to-and-return-path.md): An email has several sender-related addresses, and each one has a different job in delivery and replies.
- [DNS, PTR, and Reverse DNS](https://mailrith.com/guides/dns-and-reverse-dns.md): DNS records identify your domain, while reverse DNS helps inboxes check whether a sending IP has a sensible hostname.
- [Email Headers and Message Format](https://mailrith.com/guides/email-headers-and-message-format.md): Message headers, MIME structure, and basic formatting rules help inboxes parse and trust an email.
- [SPF](https://mailrith.com/guides/spf.md): SPF is a DNS record that lists the servers and services allowed to send email for your domain.
- [DKIM](https://mailrith.com/guides/dkim.md): DKIM adds a signature to each email so inboxes can check that an approved domain took responsibility for the message.
- [DMARC](https://mailrith.com/guides/dmarc.md): DMARC tells inboxes what to do when a message using your domain does not pass aligned SPF or DKIM checks.
- [DMARC Alignment](https://mailrith.com/guides/dmarc-alignment.md): DMARC alignment checks whether SPF or DKIM authentication matches the domain subscribers see in the From address.
- [TLS and Secure Sending](https://mailrith.com/guides/tls.md): TLS protects email while it moves between mail systems and is now a baseline expectation for bulk sending.
- [MTA-STS and TLS Reporting](https://mailrith.com/guides/mta-sts-and-tls-reporting.md): MTA-STS and TLS reporting are advanced controls for domains that want stronger protection for inbound email transport.
- [ARC and Forwarded Email](https://mailrith.com/guides/arc-and-forwarding.md): ARC helps forwarding services preserve authentication results when forwarding breaks SPF or changes a message.
- [Sender Reputation and Spam Rate](https://mailrith.com/guides/sender-reputation-and-spam-rate.md): Sender reputation is the trust inboxes build from your authentication, history, volume, complaints, and subscriber behavior.
- [Dedicated and Shared Sending IPs](https://mailrith.com/guides/dedicated-and-shared-ips.md): Shared IPs group many senders together, while dedicated IPs put more reputation responsibility on one sender.
- [Sending Volume and Warmup](https://mailrith.com/guides/start-small.md): New senders should build trust gradually instead of sending a large campaign immediately.
- [Blocklists and Link Reputation](https://mailrith.com/guides/blocklists-and-link-reputation.md): Inboxes may distrust a sender because of the sending IP, domain, email delivery service account, or links used in the email.
- [Tracking Domains, Links, and UTMs](https://mailrith.com/guides/tracking-domains-links-and-utms.md): Open tracking, click tracking, tracking domains, and UTM fields affect reporting and can influence subscriber trust.
- [Inbox Placement, Promotions, and Spam Folders](https://mailrith.com/guides/inbox-placement-promotions-and-spam-folders.md): Delivery means a receiving system accepted the message; placement is where the inbox decides to show it.
- [One-Click Unsubscribe and Opt-Outs](https://mailrith.com/guides/one-click-unsubscribe.md): Marketing emails should make it easy for people to leave, and bulk sender rules expect fast, simple unsubscribe handling.
- [Bounces](https://mailrith.com/guides/bounces.md): A bounce means an email could not be delivered, and repeated mailing to bad addresses can hurt future delivery.
- [Spam Complaints](https://mailrith.com/guides/spam-complaints.md): A complaint means someone marked the email as spam, which is one of the strongest negative signals an inbox can receive.
- [Complaint Feedback Loops and ARF](https://mailrith.com/guides/complaint-feedback-loops-and-arf.md): Feedback loops tell senders when subscribers mark email as spam, usually through email delivery service or mailbox-provider reports.
- [Suppression Lists and Subscriber Status](https://mailrith.com/guides/suppression-lists.md): Suppression protects people who should not receive normal marketing email, such as unsubscribed, bounced, or complained subscribers.
- [BIMI](https://mailrith.com/guides/bimi.md): BIMI can show a brand logo in some inboxes, but it depends on strong authentication and inbox support.