Dedicated vs Shared IP | How They Affect Email Deliverability

Chris Arrendale

5 minute read

What is the difference between a dedicated IP and shared IP in email deliverability? How do I know which one I should be using? There are several factors that come into play when deciding whether to use a dedicated or shared IP with your business.

What is a Dedicated IP?

A dedicated IP address is unique to the sender. No other company, organization, or individual can send from that IP address other than your brand. Many think they should move to a dedicated IP address because they won’t be affected by other senders and will be in control of their reputation. This is a common misconception. Dedicated IP addresses are not always the answer. We recommend that senders should only move to a dedicated IP address if:

  • You are a higher volume sender. Each ESP is different on how they view a ‘higher volume sender,’ but we recommend a minimum of 100,000 campaigns per month.
  • You have the volume to be on a dedicated IP address and other users on the shared IP address are affecting your reputation and inbox placement. This also includes blacklists and spam traps.

Be prepared to pay for your dedicated IP address, and depending on the ESP (Email Service Provider), it could be a hefty fee each month.

What is a Shared IP?

A shared IP address is shared by multiple senders. This means that a sender in Kalamazoo, MI, could be using the same IP as you in Pittsburgh, PA. For example, say you send your emails through Hubspot without a dedicated IP address. When your marketing emails are sent, you will be in a shared IP pool with other senders using Hubspot to send emails.

While a shared IP address may be good for your brand because you are a smaller volume sender, you are still sharing your reputation with other users. ESPs understand this and will try to put your brand in an IP pool that is similar to what your emails are about.

  • Always ask your ESP about the other users in your sending pool. You don’t want one bad egg to affect everyone else, and most importantly, your sending infrastructure.
  • Shared IP addresses are more cost effective than dedicated IP addresses.

It’s important to monitor each IP address your brand uses as each can affect deliverability differently. A big factor depends on the reputation of each IP address.

How a Dedicated IP Affects Deliverability

With a dedicated IP address, you are solely responsible for your reputation. First impressions are everything, and if you make one mistake (using a bad link in an email, not following proper IP warming practices, etc.), it will follow you for a while. This means if you do something to hurt your reputation with the ISPs, it will take time for them to regain their trust in you as a sender. This in turn will affect inbox placement and deliverability.

If your IP address lands on a blacklist or hits a large amount of spam traps, you’ll know that it’s nobody else’s fault except your own. From there, you can try to figure out what caused the spam trap hits.

Your sending reputation is a critical deciding factor in whether an ISP will deliver the message to the inbox or not. A dedicated IP address is easier to whitelist (Identifying you as a ‘safe sender.’ You pass through spam filters a lot easier than someone who isn’t whitelisted). For example, asking AOL to whitelist your dedicated IP address will increase your chances of an approval, versus a sender who has multiple shared IP addresses asking the same thing. Even if you get whitelisted, it’s not permanent. You can always be removed based off of your sending practices.

Another way using a dedicated IP can affect your deliverability is from sole ownership in DNS records. DNS records point right back to your brand. For example, if you were to do a reverse DNS lookup on a dedicated IP address, it would have information that is associated with your brand only.

There are a variety of solutions to increasing your reputation. Even if you’ve landed on a blacklist. Each blacklist filters differently.  After you figure out the problem, avoid making the same mistakes in the future, as these both have an effect on your deliverability.

  • You are solely responsible for your reputation
  • A dedicated IP is easier to whitelist
  • You possess sole ownership in DNS records

How a Shared IP Affects Deliverability

You are sharing your reputation. Just like the dedicated description, this can be a good or bad thing. This depends on what type of sender you are, what type of IP pool you are in, and what type of sender those other brands are that are sharing the IP address. While a shared IP address is more cost effective, your chances of hitting more spam traps and blacklists increase with the amount of companies using the IP address.

It’s difficult to whitelist a shared IP address. ISP could be nervous and say no to a shared IP address because there are multiple senders using the IP address. This then means you’ll have a harder time passing the spam filters versus a user that’s whitelisted.

DNS records don’t point back to just your company. Due to being in a shared division, the DNS records are grouped.

If you are a lower volume sender, a shared IP address may be just right for your company because you won’t have to worry about the amount of spam trap hits versus your reputation taking a plummet because of the hits.

What Next Steps Can I Take?

When deciding whether a shared or dedicated IP address is right for you, first look at the total volume of emails you send a month. Then ask yourself, is it worth getting a dedicated IP address? Factor in the cost it’ll be to have a dedicated IP.  Look at your content and how you acquire your email lists. If you don’t follow best practices, you will have to start because there’s nowhere to hide with a dedicated IP address. Weigh out the pros and cons of both a shared and dedicated IP address. If a shared IP is right for you, do research on the IP pool you are in and how your ESP groups their users.

  • Look at the volume of emails you send out
  • Factor in your budget
  • See how you acquire contacts
  • If selecting a shared IP – Do research on your pool and ESP groups/users

There are several factors that come into play when deciding whether to use a dedicated or shared IP with your business. You should choose a dedicated IP if you have a ‘high sending volume,’ want to be in control of how your reputation develops, have sole responsibility in your DNS records, and have a larger budget. For a shared IP, you must be okay sharing your reputation with a group – it’s always smart to research the group you are in because your chances of hitting more spam traps and blacklists increase with the amount of companies using the IP address. It will be harder to whitelist a shared IP, and DNS records don’t point back to just your company. However, this may be the better option if you have a smaller budget. Whichever you decide to choose, make sure to factor in all the variables above. This one decision can have a large impact on your reputation with ISPs.


For IP address help, contact one of our Deliverability Experts.

Trendline Interactive

Ready to send better messages?

About the Author(s)

Chris Arrendale

Founder of Inbox Pros (acquired by Trendline in July of 2018). Author of Deliverability Inferno. Certified expert and frequent speaker on the topics of data privacy, deliverability and compliance. BA in Poli-Sci/Soc from Emory, MS in Software Engineering & IT from Southern Polytechnic State University. A shoe and wine collection that’s the envy of pro athletes. Follow Chris on LinkedIn

Let's Take This to the Inbox

Sign up for our news, resources and updates. The inbox is our favorite place after all. We’ll make sure it’s worth it. (You can unsubscribe at any time, but you probably already knew that.)