Dedicated Versus Shared IPs for Optimal Email Marketing

An IP address serves as the base of your email communications, symbolising your digital location and history, helping Internet Service Providers (ISPs) develop information about your communications. You can either choose to have a dedicated IP, which is simply an IP address dedicated to a single user; or you can choose to have an IP that is shared, allowing multiple users to share a single IP address - and the reputation that they have collectively earned with the various ISPs. Dedicated versus Shared IPs is typically based on your sending volume and frequency, but the sender reputation that you develop with the ISPs is just as important. Whether you’re on a dedicated or shared IP, there can be benefits and serious drawbacks if you do not follow best practices and make the wrong email marketing decisions.

To fully understand this and how it applies to you, here are a couple of key factors to consider:  

  1. Sending frequency and volume explained:

To be on a dedicated IP, a minimum quantity of mail needs to be sent from it on a regular basis in order to retain its reputation. If you only send a few thousand emails once a month, it’s not likely that you will ever develop much of a sender reputation, not because you’re a bad sender, but because you aren't producing enough volume for organizations such as ReturnPath and SenderScore to index and classify you as a sender – which may result in poor deliverability. If you’re not able to maintain a sender reputation by sending out enough volume on a regular basis, you’ll never be entirely trusted as a sender, and will constantly be watched by major ISPs. To effectively utilise a dedicated IP, you need to be sending emails at least once a month, in sufficient volume, in order to maintain a sender reputation. So, you shouldn't go 30 days or more without sending on your IP. If you do, then you’ll need to send mails to smaller batches of recipients (approx. 10 000 or less) over a few days to warm it up again and rebuild that sender reputation.

Here is how to determine whether a dedicated or shared IP is best for your business:


As a general rule of thumb, if you send more than 5 000 emails per day, or at least 20 000 emails a month, you should be looking for a dedicated solution, and anything less than that means that a shared one is likely the better option for you.

  1. Your sending practice is key:

If you send a newsletter every month consistently to a million people, ISPs such as Gmail get used to your sending behaviour. They can tell that for the past six months, they've received a certain amount of mails from this particular IP address, and have the capability to track whether the recipients are opening and engaging with them.

However, if you’re sending to a substantial database after three months of not sending anything, Gmail and other ISPs will most likely interpret your mails as spam. In this case, only a small portion of these communications will be delivered, meaning your efforts have largely been wasted. The ISPs will choose to queue the bulk of your mails, to check first if your recipients are engaging with your mail, offering you a chance to complete your send, on the basis that you’re sending appealing, high-quality content.

 So what IP setup for optimal email marketing?

  1. Shared IP address:

If you don’t have a high sending volume and aren't using this facility too often, sending over a shared IP range with companies that have reputable email marketing practices will be your best option. Sharing that sending can work in your favour where there is a perception of consistent sending by everyone on that IP address, which leverages the sender reputation.

However, if you are the cleanest sender, you could find yourself being dragged down by others on your IP range, therefore ruining its entire sender reputation; but on the other hand, if your content and sending practices aren't so great, other senders will be carrying you along – however, probably not for long.

Although a dedicated IP address might seem obvious to solving this issue, you can tell from the graph (above) that it’s not always possible to be on a dedicated IP. So being on par with reputable senders and following email marketing best practices are both fundamental to ensure the best sender reputation and subsequently inbox delivery.

  1. Dedicated IP address:

If you are the only sender on a particular IP, your reputation is based entirely on your own sending practices. This gives you the advantage of not having to worry about the potentially poor behaviour of other senders.

However, to reap the benefits of a dedicated IP, you’ll still have to follow best practices (probably more so) and you have to ensure that all recipients in your database have opted in to receive your communications and that your user base is engaged.

Not taking a best-practice approach when sending and/ or making glaring errors can work against you, as you are solely responsible for these mistakes that cause blacklistings and so on. But inevitably, this will allow you to control your own course for a good sending reputation and to diagnose any issues that could emerge, without concerning yourself with other senders and their practices.

It’s clear to see that your sending volume and frequency are often the first criteria to consider when it comes to determining whether you have a need for a shared or dedicated IP, and to optimally maintain a sender reputation. Sending too many emails too frequently could work to your detriment, while the same is true for sending too few mails, infrequently. Your sender reputation will play a key role in helping you gain the most from your email marketing campaign, and improve email deliverability.

You can check the quality of your sending IP here. Your ESP should be able to provide you with this information by showing you the health of your sending IPs; and if the result is positive, you’re on the right track. However, if it’s not so good, you will at least be able to make the necessary changes to improve this. With these factors in mind, you can now analyse your general sending patterns to determine what IP setup is best for your business.

If you’re still unsure about your decision and would like more information on shared vs. dedicated IPs please don’t hesitate to contact us, at TotalSend.