Dedicated vs. Shared IP: Find the Right Fit

Chris Kolbenschlag, Director of Deliverability

Whether you are high volume email marketing sender or a small sender with a fast growing list, most likely the question of should you send on a dedicated IP or from a shared pool has been brought up internally. This is a great question and something you should take a look at carefully. Previously on the Bronto Blog we compared a shared IP to driving in a carpool (shared responsbility) and a dedicated IP to driving on your own (your responsibility). That analogy still holds true, as a dedicated IP is a single IP assigned to a single client with high volume and only their mail is sent from this one IP. A shared pool of IPs is multiple clients sending lower volume from the same set of IPs. Marketers should understand the importance of how each of these option work best and decide which is optimal.

First, there are some questions to ask yourself:

  • Are you seeing declining open rates and conversions?
  • Are you being blocked for an unknown reason?
  • Are you seeing an increase in mail placed in the bulk mail folder?

Answering yes to any of these questions could mean you are on a shared IP and a victim of poor reputation, not because of what you send, but because of the actions of other senders on your shared IP. It could also be that you are on a dedicated IP and your volume isn’t strong enough to justify being on a dedicated IP. A key component to the reputation of an IP address is cadence and volume, so a shared IP pool is the ideal option for a sender who sends infrequently and has low volume. Sharing an IP allows marketers to help each other out on reputation measurement by the ISPs so that when a marketer isn’t sending and other marketers are sending, this helps maintain steady and consistent volume on the IP. While this volume sharing helps, it can also hurt the reputation since many senders are sharing the reputation of that IP. Should one of these senders create a low performing email campaign that produces high spam complaints or high bad address bounces it could affect ALL who send on that IP, resulting in a block or bulk mail placement. Whereas a dedicated IP removes the fear of worrying what other senders are doing and puts all the responsibility on a single sender as well as maintaining the volume and cadence aspect. While both of these have good and challenging benefits, it’s important to understand what would work better for you.

This is a high-level overview of dedicated vs. shared IP. I have recently published a whitepaper continuing this discussion, to get more details on the breakdown and answer any other questions you may have, please download Improve Email Deliverability with a Dedicated IP.

Chris Kolbenschlag
Director of Deliverability at Bronto

  • Anonymous

    What do you consider low volume?

  • Anonymous

    Can you please quantify High volume vs low volumn and high frequency vs low frequendy?

  • Chris Kolbenschlag

    This is a tricky one to answer since there is another factor involved called cadence. I’ve seen client sending as low as 500,000 email a month work just fine as long as they have a consistent cadence. Meaning that sending to all 500,000 once a month will not work well with a dedicated IP but sending to 20k-40k a few times a week will.
    The other piece to this is the sender’s reputation. We have some clients on dedicated IPs sending just 2x a month and it is working well because their reputation is very clean with no spam complaints and no list hygiene issues.
    The better your reputation, the volume and cadence factor become less important. With a lesser reputation then volume and cadence do become a stronger factor that ISPs will start to look at as a positive or negative piece of their equation.
    Last, the volume and cadence factor isn’t something every ISP cares about. Some ISPs dont care when and how often you send and some are more sensitive to it.
    Thanks for the great question!