InfrastructureDeliverability

Dedicated IP vs Shared IP for Cold Email: When Each One Makes Sense

Nestmarketing Team · · 2 min read

"Should we get a dedicated IP?" is one of the first questions growing teams ask. The honest answer is: it depends on your volume and how steady it is.

Shared IPs

When you send through Google Workspace, Microsoft 365 or most sending platforms, you share IP addresses with many other senders. The provider manages reputation across the pool.

Good for:

  • Small and medium cold email programs using mailboxes
  • Irregular volume
  • Teams without someone to manage mail servers

Downside: if others in the pool behave badly, you can be affected. You also can't see or control IP reputation directly.

Dedicated IPs

A dedicated IP sends only your mail. Its reputation is entirely yours, good or bad.

Good for:

  • Steady, high volume, typically tens of thousands of emails a month or more
  • Businesses running their own mail servers (PowerMTA, Postfix, Exim)
  • Teams who want full control and visibility, including Microsoft SNDS data

Downsides:

  • A new IP has no reputation and must be warmed up slowly
  • Low or irregular volume makes reputation unstable. Mailbox providers need consistent traffic to judge an IP
  • You're fully responsible for setup: reverse DNS, TLS, bounce handling, feedback loops

The volume question

If you send 2,000 emails a month, a dedicated IP will likely perform worse than a good shared setup. There isn't enough traffic for providers to build a reputation for it.

If you send 200,000 a month on a steady schedule, a dedicated IP (or several) gives you control that shared infrastructure can't.

How we run dedicated IP setups

For clients at that scale, we typically use PowerMTA:

  • Separate virtual MTAs and IP pools for different traffic types, so cold outreach never shares an IP with transactional mail
  • Per-provider rate limits, because Gmail, Outlook and Yahoo each tolerate different speeds
  • Backoff rules that automatically slow sending when a provider returns deferral codes
  • Reverse DNS for every IP, matching the HELO hostname
  • Bounce classification that suppresses hard bounces immediately (why that matters)

Warming up a new IP

The same principle as domain warm-up, but more careful:

  • Start with a few hundred emails a day to your most engaged recipients
  • Increase gradually over 4 to 8 weeks
  • Send to Gmail, Outlook and Yahoo in proportion, not all to one provider
  • Watch deferrals and placement every day and hold volume steady if anything wobbles

Our recommendation

  • Under roughly 20,000 emails a month: mailbox-based setup across several outreach domains
  • Steady volume above that: consider dedicated IPs with proper monitoring
  • Very high volume: multiple IPs with separate pools and rotation

Not sure which fits you? Tell us your volume and goals and we'll recommend a setup.

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