Sending emails with IP rotation

Rajat K

New member
May 28, 2025
15
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As cold emailers scale outreach, a common tactic many platforms offer is:

“Rotate IPs to bypass ESP sending limits.”

Sounds great in theory.

But do real humans change IPs every 5 minutes while sending emails?

Human behaviour is the Gold standard for ESPs.

When someone sends emails manually (say from Gmail or Outlook):

  • All emails go out from one static IP unless they have different office locations.
  • The sending pattern is predictable: a few emails per hour
  • Replies are handled naturally
  • There's no spammy content or suspicious automation
Mailbox providers LOVE this behavior.

Now flip that!

If you start sending emails from:

  • A single domain (yourdomain.com)
  • Across 5–10 different IPs in a day
  • With identical or templated cold messages
ESPs notice. And they flag it.

If your cold outreach practice/tool randomly rotates IPs, you could trigger:

  • Spam classification
  • 4xx soft bounces (deferred by recipient)
  • Domain/IP blacklisting
  • Deliverability degradation, even on warmed domains
Why? Because:
  • ESPs correlate IPs with domain reputation
  • They log the source and look for inconsistencies
  • A single domain suddenly emailing from 10 different IPs = suspicious
So, how do tools like Instantly and Smartlead handle this?
What is your experience been with IP rotation?