Email Delivery IP Addresses
When emails are sent the sending mail server makes a connection to the receiving mail server. The connection is made from a specific IP address and is the first piece of information the receiving mail server utilises as part of the decision as to whether the email will be accepted for delivery.
Email delivery IP addresses contribute toward overall sender reputation so it is important that the IP addresses being used are 'clean' in order to avoid increased levels of rejected and filtered emails.
Types of IP Address
There are two types of email delivery IP addresses, 'Shared' and 'Dedicated' and either choice can be an effective method for delivering high-performing email.
'Shared' means that other senders will be delivering email using the same IP address(es) and 'Dedicated' ring-fences those resources so that there can be no external impact on delivery and engagement performance.
Shared or Dedicated?
There are no set rules as to which type should be used for email delivery but there are pros and cons to each.
Shared IP addresses are generally the best option for infrequent and lower-volume senders because they can share in the IP reputation of other established senders that are using the same IP addresses.
An obvious downside / risk is that sharing IP address reputation means that if there are issue created by another sender then it may impact on email delivery and engagement performance.
Dedicated IP addresses mitigate the risks associated with the shared approach and it also opens up to potential to creates streams of email delivery - a common example is where transactional email is delivered over a different IP address in relation to Campaigns.
'Hot' IP addresses are key to successful email delivery and to achieve this requires a number of things including regular sending, higher volume and good sender reputation - this is the main consideration when thinking about the suitability of dedicated IP addresses.
Common Questions
What does low volume mean?
It's a relative term and generally if the number of emails sent each month is less that 250,000 then shared IP addresses will usually be the best approach.
What does warming an IP address mean?
A basic summary of warming is taking a cautious and measured approach to introduce email delivery to ISPs using a newly dedicated IP address.
IP reputation is still very important which makes warming a critical component in successful email delivery. A warm-up plan can be implemented very simply and is personalised to every sender so please contact support for further details.
Can I use Shared and Dedicated?
No, shared and dedicated cannot be mixed because they need to be configured at an account level which restricts the impact of other senders.