# Authentication and Deliverability Guides > Learn how SPF, DKIM, DMARC, alignment, DNS, TLS, sender reputation, and related concepts 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 what inbox providers learn to trust. Authentication proves that your email delivery service is allowed to send email for your domain. - [From, Reply-To, and Return-Path](https://mailrith.com/guides/from-reply-to-and-return-path.md): An email can include several sender-related addresses. Each address has a separate role for delivery, authentication, or replies. - [DNS, PTR, and Reverse DNS](https://mailrith.com/guides/dns-and-reverse-dns.md): DNS records identify your domain. Reverse DNS helps inbox providers check that a sending IP address has a valid 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 read, display, and trust an email. - [SPF](https://mailrith.com/guides/spf.md): SPF is a DNS record that lists the servers and services that may send email for your domain. - [DKIM](https://mailrith.com/guides/dkim.md): DKIM adds a signature to each email so inboxes can confirm that an approved domain accepted responsibility for the message. - [DMARC](https://mailrith.com/guides/dmarc.md): DMARC tells inboxes how to handle a message that uses your domain but 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 uses the same domain family as the domain subscribers see in the From address. - [TLS and Secure Sending](https://mailrith.com/guides/tls.md): TLS encrypts email while it moves between mail systems. Bulk senders are now expected to use TLS. - [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 need stronger protection for inbound email transport. - [ARC and Forwarded Email](https://mailrith.com/guides/arc-and-forwarding.md): ARC helps forwarding services preserve email 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 inbox providers build from your authentication, sending history, volume, complaints, and subscriber behavior. - [Dedicated and Shared Sending IPs](https://mailrith.com/guides/dedicated-and-shared-ips.md): Shared IPs let many senders use the same sending infrastructure. Dedicated IPs place 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 right away. - [Blocklists and Link Reputation](https://mailrith.com/guides/blocklists-and-link-reputation.md): Inbox providers may distrust a sender because of the sending IP, domain, email delivery service account, or links 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. They can also affect whether subscribers trust your email. - [Inbox Placement, Promotions, and Spam Folders](https://mailrith.com/guides/inbox-placement-promotions-and-spam-folders.md): Delivery means the receiving system accepted the message. Placement means where the inbox shows the message. - [One-Click Unsubscribe and Opt-Outs](https://mailrith.com/guides/one-click-unsubscribe.md): Marketing emails should make unsubscribing easy. Bulk sender rules also expect fast, simple unsubscribe handling. - [Bounces](https://mailrith.com/guides/bounces.md): A bounce means an email could not be delivered. Repeatedly sending to bad addresses can hurt future delivery. - [Spam Complaints](https://mailrith.com/guides/spam-complaints.md): A complaint means a subscriber marked your email as spam. Inbox providers treat complaints as one of the strongest negative signals. - [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. These reports usually come from an email delivery service or mailbox provider. - [Suppression Lists and Subscriber Status](https://mailrith.com/guides/suppression-lists.md): Suppression protects people who should not receive normal marketing email, including unsubscribed, bounced, or complained subscribers. - [BIMI](https://mailrith.com/guides/bimi.md): BIMI can show a brand logo in some inboxes, but logo display depends on strong authentication and inbox support.