What you're doing#
You're setting up a custom envelope-sender (also called "return-path" or "MAIL FROM domain") aligned to your sending domain. Instead of AcelleMail using the vendor's default like bounces+xxx@amazonses.com, your envelope-sender becomes bounce@bounce.yourdomain.com — passing strict DMARC alignment.
This article is the 5-minute setup. For the concept + why it matters, see Return-path and envelope-sender explained.
Step 1: Pick a subdomain#
Convention: bounce.yourdomain.com or mail.yourdomain.com. Reserved for envelope-sender / return-path.
bounce.brand.com (recommended; explicit)
mail.brand.com (also common)
return.brand.com (sometimes used)
Step 2: Publish the MX record#
At your DNS host:
Type: MX
Name: bounce.yourdomain.com
Value: feedback.acellemail.com (or your install's bounce processor)
Priority: 10
TTL: 3600
The exact MX target is shown in your AcelleMail sending-domain detail page. Use that value.
Wait for DNS propagation (5-60 minutes typical).
Step 3: Configure the sending server in AcelleMail#
In AcelleMail's sidebar, Sending → Sending servers → click your active server. The detail page surfaces Connection settings + Configuration + Identity:
In the server detail's Configuration section, find the MAIL FROM (Return-Path) field. Enter your subdomain:
MAIL FROM: bounce.yourdomain.com
Save. From the next send onwards, AcelleMail uses this as the envelope-sender.
Step 4: Verify#
Send a test campaign to yourself. Open the received message → Gmail's "Show original" (or equivalent in your email client). Look for:
Return-Path: <bounce@bounce.yourdomain.com>
If you see your custom subdomain — done. If you see the vendor default (e.g. bounces+xxx@amazonses.com) — Step 3 didn't save; re-check sending server config.
Verify the DMARC alignment in AcelleMail's auth chips:
The auth chips on the sending-server detail#
Open Settings → Sending servers → click your active server. The toolbar shows the live SPF / DKIM / DMARC chip status:
- Green chips on all three = receiving servers can confirm you're authorized to send from this domain.
- Any chip red = receiving servers immediately downgrade reputation. Click Verify domain in the toolbar to walk through the DNS-fix wizard.
DMARC chip should remain Green. If it flips Red after this change, your DMARC record needs subdomain alignment too — see DMARC enforcement migration.
Common UI signals + fixes#
| Symptom |
Likely cause |
UI fix |
| Bounces stop arriving in AcelleMail |
MX record not propagated |
dig MX bounce.yourdomain.com — verify target matches AcelleMail's expected value |
| MAIL FROM field grayed out |
Vendor doesn't support custom MAIL FROM (some shared-pool setups) |
Switch to a vendor that supports custom MAIL FROM (SES, dedicated Mailgun, etc.) |
| Custom MAIL FROM saved but messages still use vendor default |
Old campaign sends using cached config |
Send a fresh test; only new campaigns use the new MAIL FROM |
| DMARC chip flips Red |
DMARC alignment lost |
Verify SPF includes the new MAIL FROM domain |
Aligned vs unaligned#
Aligned:
From: hello@brand.com
Envelope-Sender: bounce@bounce.brand.com
SPF check on: bounce.brand.com (subdomain of brand.com)
DMARC: pass via aligned SPF
Unaligned (default vendor):
From: hello@brand.com
Envelope-Sender: bounces+xxx@amazonses.com
SPF check on: amazonses.com (different domain)
DMARC: pass via DKIM only (or fail if strict alignment)
Both work for most receivers. Aligned is preferred for B2B + strict-alignment-enforcing receivers.
Advanced: multi-vendor envelope-sender management + per-tenant subdomains + automated verification
Multi-vendor envelope-sender:
If you use multiple sending vendors, each can have its own envelope-sender subdomain:
Server A (SES): bounce-ses.brand.com → feedback-ses.acellemail.com
Server B (Mailgun): bounce-mg.brand.com → feedback-mg.acellemail.com
Server C (Postmark): bounce-pm.brand.com → feedback-pm.acellemail.com
Per-vendor MX. Per-vendor sending-server config. All envelope-senders align to brand.com via subdomain leeway.
Per-tenant in SaaS context:
For SaaS sending-on-behalf-of-customers:
Customer A: bounce.customerA.com → managed by your platform
Customer B: bounce.customerB.com → managed by your platform
Each customer adds the MX record at their DNS host. Your platform's AcelleMail config sets per-customer envelope-sender.
Automated verification:
#!/bin/bash
# Daily check — verify all sending-server MAIL FROM domains have correct MX
servers=$(curl -sH "Authorization: Bearer $TOKEN" \
"https://acellemail.com/api/v1/admin/sending-servers" | jq -r '.data[].uid')
for server in $servers; do
mail_from=$(curl -sH "Authorization: Bearer $TOKEN" \
"https://acellemail.com/api/v1/admin/sending-servers/$server" \
| jq -r '.mail_from_domain')
if [ -n "$mail_from" ]; then
mx=$(dig MX $mail_from +short | head -1)
if [ -z "$mx" ]; then
echo "🚨 Server $server: MAIL FROM=$mail_from has no MX record"
fi
fi
done
Custom envelope-sender for transactional vs marketing:
Transactional server: bounce-txn.brand.com (separate reputation pool)
Marketing server: bounce-mkt.brand.com (separate reputation pool)
Bounces from each route separately. Marketing reputation problems don't pollute transactional reputation.
Vendor-specific notes:
- Amazon SES: Set "MAIL FROM domain" in SES Verified Identities. Add MX record
bounce.brand.com → feedback-smtp.us-east-1.amazonses.com (region-dependent)
- SendGrid: Whitelabel feature (paid tier). Configure via SendGrid Senders → Domain Authentication
- Mailgun: Built-in; configure via Domain → DNS Records
- Postmark: Built-in; configure via Servers → Server Settings → Custom MAIL FROM
Each vendor has slightly different MX target. Refer to vendor docs OR check AcelleMail's sending-domain detail page for the right value.
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