DarDev operates three outbound mail identities on one Stalwart MTA at mta.dardev.net: send.dardev.net for product and Listmonk campaigns, sales.dardev.net for human sales outreach, and agents.dardev.net for programmatic bot and AI SMTP only. Each subdomain has its own SPF, DKIM, and DMARC on GoDaddy while sharing the same VPS IP and PTR record. Root @dardev.net stays on Zoho for team inbox mail—a split we explain in depth in why-send-dardev-subdomain.
One physical mail server does not mean one reputation bucket. Separating channels lets product newsletters, sales sequences, and automation scripts succeed or fail independently. If a campaign list misbehaves, sales@dardev.net negotiations on Zoho and staff inboxes remain unaffected.
Shared infrastructure
- MTA host: Stalwart in Docker on dardev-vps (51.75.205.103)
- SMTP banner / PTR: mta.dardev.net at OVH reverse DNS
- Web admin: https://mta.dardev.net/admin
- Submission: port 587 STARTTLS on the internal stalwart service
- BIMI logo: default._bimi TXT on each subdomain pointing at mta.dardev.net/bimi/dardev-logo.svg
Listmonk, platform-bus, sync-worker, and Roundcube webmail connect to Stalwart over the Compose network. Operators manage DNS in GoDaddy per subdomain; Stalwart stores DKIM keys per domain after onboarding in Management → Domains.
send.dardev.net — product and campaigns
send.dardev.net is the default sending domain in the Stalwart wizard and the only domain Listmonk should use for bulk and transactional product mail. Typical From identities include news@send.dardev.net for newsletters and noreply@send.dardev.net for automated notices. Reply-To often points at contact@send.dardev.net or a staff-monitored address so replies sync back through bus jobs without touching Zoho MX on the root domain.
DNS on the send label includes MX to mta.dardev.net for inbound mailboxes, SPF TXT authorizing the VPS IP, DKIM selector mail._domainkey.send, and DMARC quarantine with aggregate reports to dmarc@dardev.net. Roundcube at webmail.dardev.net reads send mailboxes via IMAP for staff who live in the browser UI.
sales.dardev.net — sales outreach
sales.dardev.net isolates human-driven sales sequences—20.tn school outreach, DarDev Services cold pipeline, and named rep mailboxes—from high-volume product campaigns. Accounts look like sales@sales.dardev.net or per-rep addresses created in Stalwart WebAdmin. Webmail login supports send and sales domains so reps use the same Roundcube deployment with identities appropriate to each channel.
DNS mirrors send: MX to mta.dardev.net, matching SPF pattern, per-domain DKIM TXT from Stalwart after bootstrap (scripts such as setup_sales_domain.py and point-sales-dardev-dns.py automate GoDaddy records). DMARC and BIMI records follow the same template as send and agents. Sales mail still exits the same IP; receivers evaluate authentication against sales.dardev.net, not send.dardev.net, so engagement metrics for outreach do not conflate with newsletter complaint rates.
- Use for CRM-orchestrated outreach with tracked Listmonk TX where configured
- Keep From and SMTP user on @sales.dardev.net for alignment
- Reply-To can point to sales inbox on the same subdomain for reply-sync jobs
- Do not route Listmonk marketing lists meant for product news through sales domain
agents.dardev.net — automation SMTP only
agents.dardev.net exists for Cursor agents, CI notifications, and other programmatic senders that should never share credentials with marketing or sales humans. It is SMTP-only: not exposed in Roundcube, not intended for reading inbox mail in a browser. Bootstrap scripts (stalwart_agents_bootstrap.py, setup_agents_domain.py) register the domain in Stalwart and publish GoDaddy MX, SPF, DKIM, and DMARC records parallel to send and sales.
Typical accounts include bot@agents.dardev.net for agent-mail package notifications. Operators validate DNS with validate_agents_dns.py after propagation. Because automation can spike volume unpredictably, isolating agents protects send.dardev.net warmup curves and sales reputation when a script mis-fires.
Zoho root vs Stalwart subdomains
MX and SPF on @dardev.net remain Zoho for you@dardev.net staff mail. None of the three Stalwart subdomains replace that inbound path. Contact forms and executive 1:1 mail may still send from contact@dardev.net via Zoho when the workflow is CRM welcome mail, not Listmonk bulk. The inside-unified-mailer-stack guide maps how Twenty, Listmonk, and Stalwart connect across those identities.
Choosing the right domain
- Product newsletter, Hesabi digests, DarDev News opt-in confirmation → send.dardev.net via Listmonk
- Tracked school or services outreach with sales ownership → sales.dardev.net (or send per playbook) with CRM timeline Notes
- Agent runner, ops bot, scripted alerts → agents.dardev.net with dedicated service account
- Executive 1:1 or inbound customer thread → @dardev.net on Zoho, not Stalwart bulk paths
When adding a fourth subdomain, copy the same DNS block: MX, SPF ip4 plus mx, DKIM from Stalwart, DMARC quarantine, optional BIMI. Update Roundcube mail_domain only if humans need webmail on that label.
Verification checklist
After any DNS or Stalwart domain change, verify each label independently. dig +short send.dardev.net TXT, sales.dardev.net TXT, and agents.dardev.net TXT should show SPF. DKIM selectors live at mail._domainkey.{label}.dardev.net. PTR for 51.75.205.103 must remain mta.dardev.net. Send seed messages from each subdomain to Gmail and Microsoft test inboxes before raising volume.
Ops Console integrations can surface Copy TXT for DKIM to reduce paste errors. Keep SMTP passwords in VPS env vars and Stalwart accounts—never in git, static news JSON, or article drafts.
Why three domains on one IP?
Authentication and reputation are per domain, not per IP. One MTA reduces operational cost while SPF/DKIM/DMARC alignment scopes each channel. PTR points at mta.dardev.net for all outbound SMTP.
Can Listmonk use sales.dardev.net?
Only if you deliberately configure a separate messenger for sales campaigns. Default Listmonk SMTP stays on send.dardev.net with news@ or noreply@ identities. Sales outreach often uses platform-bus send-one with templates tied to the sales domain per playbook.
Is agents.dardev.net in webmail?
No. agents is programmatic SMTP only. Roundcube allows send.dardev.net and sales.dardev.net per custom.inc.php mail_domain settings.
What happens if I send bulk mail from @dardev.net?
SPF and DKIM will not align with Zoho's inbound configuration; DMARC failures rise; employee mail reputation can suffer. Use send or sales subdomains per why-send-dardev-subdomain.
How do BIMI and DMARC interact across the three domains?
Each subdomain needs its own _dmarc label with p=quarantine or reject before BIMI inbox logos apply. Gmail and Yahoo may require a VMC certificate in the BIMI record after trademark verification—same logo URL on all three.
