Three Ways To Warm-Up Your IP Addresses (& Keep Them Hot)

There you are. The great outdoors.

The tent is pitched. Marshmallows, graham crackers, and Hershey’s chocolate sit nearby as your friends and family gather near the fire pit. You’ve got the firewood, kindling, and matches, but the only heat you’re feeling is that of embarrassment because try as you might, you can’t start the fire.

Strike…strike…spark…and out goes the match yet again. Without fire, there will be no dinner or delicious s’mores for dessert. If you only had your firestarter kit, you would have everything you need! If you could just get it started, you are sure you would be able to keep it going…

Now, imagine that you have a brand-new IP address. Your subscribers have gathered around, waiting to hear from you. But unless you know how to warm-up your IP address with the Internet Service Providers (ISPs), they likely won’t accept your campaign, and your subscribers will be left in the cold with no dinner and no dessert. Yikes.

As you’ll see in today’s post, one of the keys to running an email server is not only knowing how to effectively warm-up an IP address but also how to keep that fire going so your deliverability (and profits) don’t end up fizzling out. OK, let’s get into it!

Getting that fire started…

When you’re sending email from a new IP address, it’s important to start out with a small volume of email and then carefully build that volume over a period of time. Much like in starting a campfire: you first light small sticks, which as they burn ignite larger sticks, which then get the logs going.

You have to start small because your IP addresses start out with no reputation, and ISPs limit the amount of email they will accept from IPs with no reputation. The quality of this early email builds the IP address’s reputation — which lets you send more — which builds even more reputation.

Why this confidence-building exercise? A common tactic of spammers is to obtain a new IP address, then quickly send as much email as possible before it gets blocked, then obtain other new IP addresses and repeat. And repeat, and repeat. So you really can’t blame the ISPs for being suspicious of email from IP addresses without any reputation.

If you’re using software (like GreenArrow) that’s capable of sending millions of messages per hour, and you’re starting with freshly assigned IP addresses, it’s important to control your need for speed. If you run the software full-blast and ignore these speed limits, you’ll hurt the reputation of your IP addresses and deliver less email.

You can avoid this type of problem by warming up your IP addresses. There are three basic strategies from which you can choose:

Strategy 1 – Build Your Own Warm-Up Plan

Your first option is to develop and execute your own IP warm-up plan. This includes thorough planning, regular monitoring of key stats, and careful execution.

A prerequisite to building your warm-up plan is to develop an IP segmentation plan. The number of IP addresses you need will depend on the type of email you’re sending, and how much of that type a single IP can support. For example, you can use some IPs for confirmation emails and other IPs for marketing campaigns. We dig into that topic further in Multiple IP Addresses: Why and How Many?.

Also, when you obtain your new IPs from your hosting provider, be sure to verify that the IPs aren’t currently on any major blacklists. If they are, consider asking for replacements. It can be tough to start off with IP addresses that are “in the hole.”

Once your IP segmentation plan is in place, you can start planning for the warm-up. Our post Your New IPs Need to Learn to Walk Before They Run lays out a six-part basic strategy:

  1. Pave the road. This includes configuring DNS records and feedback loops. (See Adding a New IP Address for an overview of our suggested sequence.)
  2. Create a segment of active email addresses.
  3. Send messages that are relationship-building in nature.
  4. Monitor your delivery metrics.
  5. Execute your plan by ramping up the volume—slowly.
  6. Keep putting your best foot forward and monitor your progress.

Strategy 2 – Work with a Deliverability Consultant

Having someone on your team who has gone through the IP warm-up process before can be invaluable (like a firestarter kit). If you’re not already experienced with this process, then I recommend working with a deliverability consultant.

How hands-on you want your deliverability consultant to be is ultimately up to you. You could ask them to simply design a warm-up plan and then leave the execution to you. Or you could have them design and manage the entire IP warm-up process (or anything in between).

If you’re looking for ways to save money on deliverability consulting without compromising on results, then I have a few tips:

  • Become familiar with your email software’s deliverability-related metrics and throttling configuration settings. Having a solid understanding of those two areas will help your deliverability consultant work more efficiently with you. If you’d like some help in these areas, then it’s worth checking with your email vendor on what training options are available.
  • Check with your current email vendor to find out if consulting is included. For example, GreenArrow licenses often come with a block of deliverability consulting time, so be sure to review this with your account manager.
  • If you’re in growth mode (meaning the number of emails you send will increase this year), but your plan doesn’t include adding a new staff person to handle deliverability (which is very common), we suggest budgeting for a monthly check-in with your consultant. Whether it’s a GreenArrow consultant or another firm, many consultants can provide hourly or retainer options to meet your needs. Be sure to ask what they can offer you.

Strategy 3 – Use a Shared IP Pool (a la Sherlock Holmes)

Sometimes using a shared IP pool makes sense, even after you’ve started using software which supports dedicated IPs.

Even Sherlock Holmes agrees:

“…while the individual man is an insoluble puzzle, in the aggregate, he becomes a mathematical certainty. You can, for example, never foretell what any one man will do, but you can say with precision what an average number will be up to. Individuals vary, but percentages remain constant.” The Sign of Four by Sir Arthur Conan Doyle

Holmes’ observation of 19th-century life holds equally true today. Given a large enough sample size, averages become predictable. Believe it or not, one of the areas this principle applies to is email. And it’s most often the case for senders who send a low volume of email or whose email sending is very “bursty” (i.e., sent in bursts).

Infrequent sending (less than once every week or two) can cause deliverability issues when using dedicated IPs, but if you take multiple email senders who have bursty sending patterns in isolation and put them into a shared IP pool, their traffic patterns get smoothed out.

As an example, let’s look at a 24-hour interval, and compare the traffic patterns of two of DRH’s cloud customers to the shared IP pool that they’re both in.

Customer A sent nearly all of the day’s emails within the span of a few early morning hours. The scale on the left shows messages per hour:

Customer A Bursty Email Sending Pattern

Customer B had three primary periods of sending. Two were in the morning, and one in the early afternoon:

Customer B Bursty Email Sending Pattern Both of these customers have bursty sending patterns. They send each day’s email over the course of a few hours and are otherwise mostly idle.

Here’s the cool part. When you take multiple customers like the above and combine them into a shared IP pool, the peaks and valleys in the graph get smoothed out and everybody wins. Here’s a graph of a shared IP pool’s activity during the same period:

Shared IP Pool Graph There are still peaks and valleys, for sure, but email volume is much more evenly distributed throughout the day, a Sherlock Holmes teachable moment.

This example is over the course of a day, but the same principle holds over weeks. If you send too infrequently to maintain a dedicated IP reputation or simply want our team to take care of these details, then a shared pool may be the answer. Many of our cloud customers use their own dedicated IPs, but we maintain and police a pool of shared IPs used by customers whose mailing patterns are complementary.

Don’t Let Your IP’s Reputation Fizzle Out

Just like that campfire, once your IP address is warmed-up, it won’t stay that way permanently. If you stop sending mail via a previously warmed-up IP, then you could find yourself starting the warm-up process all over again.

It’s important to monitor and maintain your IPs, possibly with help from a professional. A once a month checkup from a deliverability consultant could ensure that everything is running smoothly. Such a checkup should include the following:

  • Maintaining good list hygiene. This includes promptly honoring unsubscribe requests, deactivating bad addresses, and sending only to subscribers who have recently engaged with your emails.
  • Monitor your acceptance, deferral, bounce, spam complaint, inbox, and spam folder rates. (Any sudden or unexpected changes for the worse in these stats will be the first indicator you may have a problem.)
  • Verify that you’re continuing to send enough email to maintain your reputation.
    • For example, if you want your IP addresses to be warmed-up enough to be able to send a million messages per day, then on an average day, they should send a substantial portion of that figure.
    • How much is needed is dependent on a number of factors. If you don’t have historical data to show you how much is enough, then a deliverability consultant should be able to offer some guidance.

How Hot Is Just Right? Depends On What You’re Cooking

You may be wondering which of the three strategies will work best for you, or what steps you need to be taking to keep your reputation smokin’ hot. The short answer is that while there are many best practices outlined above, each sender’s goals (and sending patterns) can be wildly different. Not only that but depending on the email software you’re using or the email program you’re building—your best steps may look different from the next sender.

Because of this, it’s worth discussing these strategies with your team and/or with your software provider. Whether you send on an infrequent or “bursty” schedule or need to ramp up more slowly than the average sender, choosing your next step could be just as critical as a fire ignitor or kindling to keep it all going.

As always, we’re happy to take any questions, or you can request a demo to learn more. Keep it warm and happy sending!


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