Cold email infrastructure is the set of secondary domains, mailboxes, authentication records, and sending tools used to run outbound campaigns without risking a company's primary domain.
What good looks like#
- Done: Register 2 to 5 lookalike domains and redirect them to your main site.
- Done: Set up SPF, DKIM, and DMARC on every domain from day one.
- Done: Create 2 to 3 mailboxes per domain and warm each for 3 to 4 weeks.
- Done: Cap sends at 30 to 50 per mailbox per day and rotate across mailboxes.
- Done: Monitor bounce and reply rates per mailbox; retire any that degrade.
What bad looks like#
- Seen in audits: Sending cold mail from the primary company domain.
- Seen in audits: Skipping DMARC on secondary domains because 'they do not matter'.
- Seen in audits: Buying aged domains with unknown history.
How to move from bad to good#
Work through the good list in order and re-verify after each change. Most teams find one or two items from the bad list already present; fixing those usually produces the largest improvement.
Frequently asked questions#
How many emails can I send per mailbox per day?
Google Workspace allows 2,000, but for cold outreach 30 to 50 keeps you under behavioral thresholds.
Should I use Google Workspace or Microsoft 365 for cold email?
Both work. Workspace mailboxes tend to warm faster; Microsoft has stricter outbound spam filtering.