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Deliverability: dedicated or shared IP? by Jean-Michel Radiskol, Chief Deliverability Officer at Adobe

Adobe-CampaignNowadays, in one minute, more than 200 million emails reach ISPs and webmails around the world with varying degrees of success. In order to be able to differentiate and guarantee a good deliverability to your emails, there is a key point, the reputation.

Reputation can be assimilated to the footprint that a company will leave on the web. In the case of emailing this will be based on the IP and/or the (sub)domain.

Many companies, even big brands, have lost their reputations due to poor communication and/or address collection practices. The name of a brand is not enough to create a good reputation against Webmail such as Hotmail or Gmail.

Good practices are the key to success.

It seems then necessary to give visibility on the two main strategies that can be put forward to guarantee a reputation, as well as the advantages and disadvantages of each in terms of IP strategy. This strategy is divided into two main categories: dedicated IP and shared IP.

However, before even choosing one of these two strategies, it is crucial to understand why these two strategies exist through the ISP rules and correlate them with the sender's activity.

Of the 200 million emails mentioned above, a large majority is what we call SPAM, unsolicited email. It is therefore important for ISPs and Webmail to protect their users.

Among the many rules to be respected (double opt-in, segmentation, commercial pressure, HTML, etc.), one of the main ones is based on the consistency of mailings over time and volumes, in order to create and maintain the reputation of IPs and sending (sub)domains.

The question is: what is the right strategy to implement for a new emailing project: dedicated or shared?

  • The dedicated IP is generally an IP with no known traffic, virgin of reputation that will be entirely dedicated to the email traffic of a brand, a sender.
  • Shared IP is as the name implies, a common vector of email traffic between multiple brands/senders, which implies that a good or bad reputation is already established.

A preliminary phase is necessary from the consultant or the router to expose the advantages and disadvantages but it is also the right time to ask the right questions about its strategy and its emailing practices.

Choice and implementation of a dedicated IP

This choice implies two primordial phases which are the construction and maintenance of the reputation.

The newly implemented dedicated IP has a neutral reputation, so it is advisable to set up the reputation building process via a ramp-up or a warm-up which is the first phase.

Reputation building is done via a ramp-up or a warm-up, which consists of gradually increasing the volume. This progressive increase allows to respect the rules of the ISPs but also to move from one solution to another in one-shot. The ramp-up phase generally lasts from 2 weeks for the smallest customers, and can extend to 6 or 8 weeks for the largest senders with a high proportion of email addresses considered inactive or dormant. During this phase, corrective actions can be proposed.

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Once the reputation has been built during the ramp-up phase, it is useful to emphasize that it must be maintained and reflected on each of the sendings that will be made via the IPs during the second 'on-going' or 'production' phase. Spam filters that manage reputation are nowadays hyper reactive and adapt reputation in real time.

The three key advantages and disadvantages :

  • Advantages :
    • Reputation management,
    • Certification program available,
    • A full-branding configuration on the sender's (sub)domain name (if delegated to the ESP or MSP).
  • Disadvantages :
    • Ramp-up phase,
    • Regular mailing frequency (3-4 times a week),
    • Volume consistency (+/- 25% difference from one day to the next).

Choice and implementation of a shared IP

The choice of a shared IP is mainly proposed to small senders being under the 2 million emails per month and having a database around 750K contacts and not being able to send on a regular basis.

The idea is to mutualize the volume of these different senders in order to reach a critical mass and a sufficient frequency.

It is essentially up to the ESP or the MSP to decide whether or not to mutualize a particular sender. This decision is theoretically based on a preliminary study of the activity and history of the candidate for the shared IP.

This strategy offers more flexibility in terms of integration because no ramp-up phase is necessary. However, in order to protect the senders already implemented on the shared IPs, it is required to integrate the senders in several waves in order to control the quality of the database, the reactivity of the contacts and the influence of the new sender on the shared IP. As during the ramp-up phase of the dedicated IP, corrective actions can be imposed, failing which the sender may be excluded from the shared IP.

The three key advantages and disadvantages :

  • Advantages :
    • More flexibility on sending frequencies and reduced ramp-up phase.
    • More flexibility on shipment volumes,
    • All senders work on building the reputation of the PI.
  • Disadvantages :
    • A single sender can negatively impact the entire reputation,
    • No certification program available,
    • A common reverse DNS.

Without differentiating the chosen strategy, a special attention will be brought during the first sendings because they will make it possible to take note of the quality of the sendings, as well as the performances of the latter.

Corrective actions must be taken quickly if necessary to limit the potential negative impact.

To conclude, it is important to work in an open and transparent way with the solution provider or consultant in order to choose the best technical solution to implement, as well as to take into account the optimizations of your marketing plan.

The reputation of an IP is not simply an element linked to opt-in legislation, it is a complex alchemy in a real life cycle taking into account local legislations, ISP rules and user reactivity.

It is understood that the strategies proposed above do not apply to real-time message sending strategies. The tiny volume spaced in time, as well as the messages themselves, are sufficient to maintain the reputation of the IPs.

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2 réponses

  1. Very good article. Very clear. Thank you.
    I would say that a new dedicated IP (or IP range) has a slightly negative reputation at the beginning. It is up to the first senders to help establish the initial neutral or even positive reputation. And this takes some time.
    It is therefore important to be careful not to clean up your database at the first sending and to be very careful with the initial import by making sure that the known unsubscribers and NPAIs have not been imported by mistake.
    The first such shipment would do great harm to the nascent reputation of the IPs and the sender and would require even more time to restore.

  2. Thank you.
    It is also important to note that during this ramp-up phase, senders should be encouraged to use active contacts such as openers from the last few months to boost reputation, especially on Gmail, Yahoo and Hotmail.

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