From, Reply-To, and Return-Path
An email can include several sender-related addresses. Each address has a separate role for delivery, authentication, or replies.
Overview
People often describe an email as coming from one address. In practice, a message can include several sender-related addresses, and each address has a different role.
The From address is the visible sender that subscribers see in their inbox. In newsletter@example.com, the visible From domain is example.com. Subscribers usually use this address to decide whether they recognize the email.
The Reply-To address tells the email app where to send human replies. Reply-To can use the same address as From, or it can use a different monitored inbox, such as support@example.com. Reply-To affects human replies only. It does not affect DMARC alignment.
The Return-Path address is usually hidden from subscribers. It is also called the envelope sender, bounce address, MAIL FROM, or smtp.mailfrom. Delivery failure messages are sent to this address, and SPF checks this domain.
The DKIM signing domain is another sender-related domain in the message headers. It appears as d=example.com in the DKIM signature. DKIM checks whether the signature is valid.
DMARC Alignment compares the visible From domain with the SPF domain or the DKIM signing domain. DMARC does not compare the Reply-To address. Because of that, changing Reply-To cannot fix a DMARC alignment failure.
In a clean setup, these addresses and domains work together. For example, subscribers see newsletter@example.com, replies go to hello@example.com, bounces go to bounce.example.com, and DKIM signs with d=example.com.
What to Do
- Choose the From address that subscribers should recognize.
- Choose a Reply-To address that your team actively monitors.
- In your email delivery service, configure DKIM so the DKIM
d=domain matches or aligns with the From domain. - If your email delivery service supports a custom Return-Path or bounce domain, configure one so SPF can align too.
- Create or update the Email Delivery Connection in Mailrith with the correct From name and From email.
- When you send a broadcast, sequence, or automation email, set Reply-To only if replies should go to an address other than the From address.
- Send a test email. Then inspect the original headers and confirm that From, Reply-To, Return-Path, SPF, DKIM, and DMARC show the expected domains and pass or fail status.
What to Check
- From sets the visible sender identity.
- Reply-To controls where human replies go.
- Return-Path receives delivery failures and is used by SPF.
- DKIM
d=is the signing domain used by DKIM and DMARC alignment. - Changing Reply-To does not fix SPF, DKIM, or DMARC.
- If bounces are not reaching Mailrith, check your email delivery service webhooks and Return-Path behavior.
- If replies disappear, check the Reply-To address and confirm that your team monitors that inbox.
Fix Common Issues
Sender Domain Cannot Receive Replies
An MX record check found no MX records for a sender domain. Some sending-only subdomains are intentional, but a sender domain without receiving records can confuse replies and reduce operational trust.
- Decide whether people should be able to reply to the From address.
- If replies should work, add mail receiving records through your mailbox provider, or use a From domain that already receives mail.
- If replies should go to a different inbox, set a monitored Reply-To address in Mailrith.
- Send a test email, then reply to the test email from a real inbox.
- If the sender domain is intentionally send-only, document that choice so your team does not mistake the missing receiving records for a delivery failure.
Note
When you troubleshoot authentication, compare From, Return-Path, and DKIM d=. When you troubleshoot replies, check Reply-To.