Dedicated IP for email: when you need one and how to set it up

A dedicated IP is an IP address used exclusively by one sender. On a shared IP, dozens or hundreds of senders share a pool managed by an ESP. On a dedicated IP, every bounce, complaint, and engagement signal is yours alone, for better or worse.

Dedicated vs. shared: the real trade-off

Shared IP is the default at most ESPs. The ESP monitors pool quality and removes bad actors. You benefit from the accumulated reputation of the pool without doing anything, and you do not need to warm the IP yourself. The downside: a careless sender in the same pool can affect your deliverability, and you have no direct control over it.

Dedicated IP is your personal sending history. Filters evaluate your mail based solely on what you have sent in the past. That is the appeal, but it comes with a catch: a fresh IP has no reputation at all, and ISPs treat unknown senders with suspicion by default.

When it makes sense

Volume above 50,000 to 100,000 messages per month is the floor. Below that, you rarely send enough to give ISPs a reliable reputation signal, and a quality shared pool will outperform a low-volume dedicated IP. Regular cadence matters too: if you blast quarterly and go quiet in between, the IP reputation decays between sends.

Dedicated IPs also make sense when you want to isolate transactional mail from marketing. Order confirmations and password resets land differently from promotional emails, and putting them on separate IPs keeps a spike in marketing complaints from delaying your receipts.

When it does not

Under 50,000 messages per month, a shared IP is usually the better choice. The ESP-managed pool carries years of positive reputation that a small sender cannot build alone. And if your list is unclean, a dedicated IP makes things worse. On a shared IP, your errors are partially offset by other senders' good behavior. On a dedicated IP, every hard bounce and spam complaint lands directly on your address with nothing to absorb the impact.

Setup checklist

Configure a reverse DNS (PTR) record so the IP resolves to a hostname that in turn resolves back to the same IP. Update your SPF record to authorize the new address. Confirm DKIM signing works from it. Then warm the IP over two to four weeks, starting with your most engaged subscribers and ramping volume gradually. Skip the warmup and you risk deferrals before you have sent a single campaign.