Short answer: never send cold emails from your main domain. Use secondary domains, a few mailboxes per domain, full authentication and a custom tracking domain. Here's the complete setup.
Why not your main domain
Your main domain sends invoices, support replies, product emails and internal mail. If cold outreach damages its reputation, all of those start landing in spam too. Secondary domains isolate the risk.
Step 1. Buy secondary domains
- Pick names close to your brand: getcompany.com, trycompany.com, company-hq.com
- Prefer .com or your main market's extension. Unusual extensions look suspicious.
- Avoid hyphens and numbers when possible
- Redirect each domain to your main website, so prospects who check it land somewhere real
Step 2. Create mailboxes
- Use a real provider (Google Workspace or Microsoft 365)
- Use real first names (firstname@getcompany.com), not sales@ or info@
- Keep a small number of mailboxes per domain, typically 2 to 3
- Add a profile picture and a signature matching your main email
Step 3. Set up authentication
- SPF: authorize your email provider to send for the domain
- DKIM: enable signing in your provider's admin console and publish the record
- DMARC: start with p=none plus a reporting address, then tighten later
- Check everything with a DNS checker before going further
Step 4. Set up a custom tracking domain
If you track anything, use a custom tracking domain (a CNAME on your secondary domain). Shared tracking domains carry the reputation of every other sender using them.
Step 5. Warm up
- 3 to 5 weeks before the first campaign
- Warm-up target equal to your planned daily campaign volume
- Keep warm-up running once campaigns start
Step 6. Plan capacity
Work backwards from your volume goal:
- Target: 300 cold emails a day
- At 30 to 40 per mailbox: 8 to 10 mailboxes
- At 2 to 3 mailboxes per domain: 3 to 5 domains
Add spare mailboxes so you can rest one that shows warning signs without stopping outreach.
Step 7. Keep your domains under the bulk threshold
Google treats a domain as a bulk sender once it sends around 5,000 emails in 24 hours, and the status is permanent. Spreading volume across domains keeps each one well under that limit.
Common mistakes
- Sending from the main domain "just for a test"
- Launching the day after buying the domain
- Creating 10+ mailboxes on a single domain
- Skipping DMARC because SPF and DKIM pass
- Using a shared tracking domain
How lemlist handles it
- Connect Google Workspace, Microsoft 365 or SMTP mailboxes
- Built-in checks for SPF, DKIM, DMARC and custom tracking domain
- lemwarm warm-up for every mailbox
- Several senders on one campaign, with sending spread across them
Planning a new setup? Share your target volume and we'll help you size domains and mailboxes.
Source: r/lemlist_official · by /u/sent_from_lemlist