Many email service providers and marketing automation vendors offer a choice between sending email with a shared IP or a dedicated IP. As more and more consumers of these services learn about deliverability, some marketers have started to assume that a dedicated IP will be the best choice for every sender. It’s not that simple.
Let’s start with a little background. I like to tell my customers to think of email reputation as similar to a credit score. While the credit score process in the US is more formal and centralized than email reputation, the metaphor holds true in many respects. Email reputation is the positive or negative rating given to messages with something in common – usually the sending IP (reputation may also be attached to linked domains or other key pieces of information in the message content). With a credit score, having no credit is treated similarly to bad credit; this is the same with email reputation.
Major email receivers and antispam services keep track of email reputation by keeping track of the spam scores of and user response to email sent through their systems. If a large number or percent of the messages coming from a specific IP generate clicks on the spam button or other red flags, the IP will start to get a poor reputation, which can result in junk foldering and outright blocking. Because the overall email landscape is so saturated with spam and malware, antispam systems cannot afford to trust unknown senders with no reputation, so these IPs are treated to additional checks and limitations in the same way that questionable senders are.
To become a known sender, a given IP should send a certain volume and frequency of mail. These institutional memories don’t last forever, so most reputation systems tend to reset after a few weeks. Similarly, it’s hard to get a good measure of reputation with only a small trickle of messages to review, so sending below a certain threshold may mean your IP doesn’t accrue reputation at all – even if your messages are great and don’t generate any complaints.
Dedicated IP senders will only have their own email patterns to rely on, while shared IP senders can take advantage of shared volume and consistency to maintain a good reputation. When using a shared IP to send, you’ll rely on your provider’s policies and abuse team to maintain a good sending reputation for your IP. If you choose a quality vendor, you can enjoy the benefits of a great reputation without having to send at the volume and frequency necessary to maintain a good reputation on a dedicated IP.
When evaluating your IP needs, consider your average daily, weekly and monthly sending volumes. There are no specific rules for how much mail should be sent through a single IP; experts recommend anywhere from an average of 100,000 per month to as much as 50,000 per day before moving to a dedicated IP. Check with your chosen vendor for their specific recommendations.
Some companies will see great advantages to sending with a dedicated IP, but it’s not the right strategy for every sender. Low volume and infrequent senders will often see a shared IP out-perform a dedicated IP. If you are considering sending from a dedicated IP, check with your provider for their recommendation. I hope that this post will help you make the right choice for your organization.