Deliverability of your emails

Deliverability explained in detail by mailpro

10 Questions/answers brief


The deliverability of emails is one of the most important criteria of an emailing campaign. Deliverability is the ability of an emailing to be routed from the sender to the recipient, in a timely fashion and in its entirety. Deliverability therefore expresses the fact of establishing contact with prospects.

A good deliverability guarantees mailings received inboxes that can then be opened or clicked. This is a real economic stake for your campaign: sending emailings that do not arrive at their destinations will be very expensive and unnecessary, so no ROI. Moreover, emailings which are not placed in inboxes make your campaign strategy ineffective and negate your marketing efforts.

Mailpro focuses on deliverability. First, Mailpro offers ultra fast and efficient routing that guarantees access to inboxes. However, you can lose deliverability due to identification as spam or mismanagement of your database. For this, Mailpro accompanies you with the emailing blog and offers you this brief on 10 advertiser misconceptions on deliverability.

1. Deliverability is an extremely simple concept: false

Deliverability measures through emailing numbers and statistics the ability of email campaigns to reach the prospects inboxes. Deliverability is not a simple concept because many dimensions can have a negative effect on deliverability. In the same way that poor deliverability will negatively impact other aspects of your campaigns. Here are some examples:

Criteria that may adversely affect the deliverability:

  • Be identified as spam (bad email subject, body)
  • Prospects report you as junk mail
  • Sending emailings without using a professional solution as Mailpro
  • Using false sender addresses or bounces
  • Complaints from prospects to organizations or yourself

Poor deliverability will impact:

  • Your e-reputation
  • Your IP address will be blocked by ISPs
  • You will be blacklisted temporarily or permanently
  • Your entire campaign will be discounted

Deliverability is far from a simple concept because it is at the center of an equation with multiple variables. So you must constantly observe your deliverability with your emailing statistics.

2. Deliverability is just a matter of sending: false

Deliverability is not just a matter of sending. Indeed, by sending mass mailings, it is quite possible that you will get responses in return. Whether it be prospects, organizations or even the ISP, you will have to answer them, or at least put in place a response system management. If you do not respond to those complaints or to the ISP requesting additional information, your e-reputation will drop and eventually you will be considered as an advertiser with bad practices and you will be blacklisted.

The answers will then be treated differently but also be sent with precise email addresses, of which the title is adapted to the nature of the response.

  • postmaster@...: this address type is very common and it is the least specific of all. There is a catch-all address, through which you can communicate with prospects about a complaint or question.
  • fbl@... : This is clearly the address that will allow you to manage complaints about the overall feedback loop.
  • abuse@... : This address allows you to handle complaints through which you are reported as spam.
  • alerts@... : will allow you to retrieve different elements called warning, such as actions identified as triggers for automation.

As you will be receiving emails, you will also need an email filter on your side. First, to make storage in your Inbox, depending on the type of email you receive, but also to avoid spam.

3. For my deliverability, the domain name is irrelevant: false

You have a domain name for your website, and usually hosts offer you email addresses "matched" to the domain. On your deliverability, two cases are discernible: the first is when you send emails with an address with the same domain name, the second is when you deal in sending mailings with your own domain name.

Let us take a closer look at the first case: you have decided to send an email campaign with an address that has the same domain name as your website. Only, imagine that the sending of this address has a poor deliverability and you find yourself blacklisted or banned. In this case, your domain name put in danger, and therefore your site as well. It is preferable to use subdomains to the mailing. Similarly, you can opt for a subdomain by type of emailing and the poor deliverability of your promotional campaign will not tarnish your loyalty campaign.

Regarding the second case, you send this time an email campaign of one of your partners with your own domain name. Similarly, in case of bad deliverability, you put your online reputation on the line on behalf of someone else. If you do this with multiple partners, you can opt for different domain names (which can be subdomains of the same domain) with dedicated IP addresses. We will see later that the shared IP addresses are not really recommended in such cases.

4. Deliverability has nothing to do with the ip address: false

IP addresses and deliverability are related. Indeed, IP addresses are tied to the mailings you send, so they are a parameter of your campaign and can impact your deliverability. In addition, an email campaign does not mean a single IP address.

Indeed, the estimated number of mailings sent determines the number of IP addresses to use. If you do not plan enough IP addresses to route your mailings you will be blocked, and on the flip side, ISPs find particularly suspicious to allocate more IP addresses to a campaign then necessary. For a given volume of mailings sent, we prefer dedicated IP addresses, while for smaller volumes we can opt for IP pools.

IP pools

IP pools correspond to shared IP. With this system it is easy to determine the proper volume of mailings sent but also to make shipments for several types of campaigns. However, as previously evoked, poor deliverability of a campaign can affect that of others. In addition, the sharing of IP must be made equally among the different campaigns, if not, ISPs will be intrigued to see the flow of very different sizes.

Dedicated IP

Dedicated IP are particularly effective in the context of sending large volumes (> 10,000 mailings per day). And for very large shipments, you can choose a dedicated IP pool, that is to say from IP subdomains of the same domain. With dedicated IP, you have a single stream for each campaign, so there are no interactions.

Buying IP

You can also buy IP, this allows you to keep your IP, what ever happens, even if you change providers. Your work on the e-reputation of your IP is well preserved regardless of changes in your provider. However, the purchase of IP adds an additional cost to your email campaign.

Once you have your IP address(es), you must include them in the WHOIS, which is a directory of domain names. The different email addresses mentioned above will also appear. This registration is important, it formalises your domain name and allows you to be found, including being placed in the white list of ISP.

You can then perform several tests on your IP before the release of your campaigns:

  • Reverse DNS: make sure the IP is your domain name and vice versa.
  • IP history: check e-reputation of the chosen address and its history.
  • View the IP address on your site to give information easily to ISPs

5. Deliverability can not be impacted by id theft: false

As an advertiser, you are not immune to identity theft. If this is the case, a spammer might use your domain name and your address and then you lose all the qualities of your deliverability. To avoid ID theft you must protect yourself with an authentication procedure. Several solutions are possible:

Authentication can actually protect your future deliverability from ID theft, so it should not be overlooked.

6. Bounces don't impact deliverability: false

Bounces befall when you send an emailing to an address that does not exist or a full inbox. You will receive an email giving you the reason why your emailing has not been issued. Managing bounces is important for deliverability.

In emails that are returned to you after a bounce, a code gives you the type of bounce. Here is the correspondence between the code and the type of bounce:

  • VERP: allows automatic detection and removal of addresses for mailings which are not distributable. Wikipedia gives the following example:
  • Envelope sender: wikipedians-owner + bob = @
  • Recipient:

The bounce will be: wikipedians-owner + bob = @ with an empty envelope sender.

  • The hard bounce: this bounce signifies to the sender that the email address is not valid. The code is: Diagnostic-Code: smtp; 550 No such user here
  • The soft bounce: the bounce that is sent when the recipient's inbox is full or temporarily unavailable with code: Diagnostic-Code: smtp; 552 Mailbox full

There are other types of bounces, less frequent, but that are necessary to fix. Bounces are the best way to understand why your mailings have not arrived at their destination, and thus to change your mailings to improve your deliverability.

7. The header of my mail is not important: false

Emailing headers are seen first by anti-spam filters, it is necessary to learn how to properly build a header, which will guarantee a good deliverability. Here's what to include:

  • An email address for complaints, the famous abuse@ or even a link to a complaint form (rare).
  • A link to a page to unsubscribe.
  • Data that identifies you as the sender.
  • Signal that you are doing a mass mailing by adding "Precedence: bulk".

8. There is no need to join lists before you start to send: false

Several white lists and records exist and identifies advertisers with good practices. So you can register yourself (your IP address, your domain name, etc.) On these lists to ensure the deliverability of your campaigns:

  • ISPs white lists
  • to register your abuse@ address
  • Acquire various certifications that exist on the net
  • which is the largest white list of advertisers

9. I do not need to oversee my deliverability: false

First, you need to watch your deliverability with your various tools, such as emailing statistics. Moreover, deliverability is also observed with bounces, your level of online reputation or the effectiveness of your feedback loops

Deliverability is a long term battle. Indeed, changes are made over time and it is a fight on several fronts so you're forced to spend time throughout. Also, deliverability is constantly changing, so you must be ready at all times. Similarly, you need to keep track of the white and black lists to see where you stand.

Deliverability is also observed with respect to changes in techniques of anti spam filters. To go to inbox, you must be able to understand how the filter is made and what ISP expect of you.

Finally, overseeing deliverability is done by oversseing e-marketing techniques, constantly searching for optimizations.

10. Deliverability has no more secret: false

Here's one last point of vocabulary.

Bulk: identifies your mailings as such in the header. Moreover, the fact that emailing is routed to junk rather than the inbox is called the phenomenon of bulking.

Unsubscribe: it relates to unsubscribing to newsletters or mailings of a brand or a company. To unsubscribe is a fundamental right for prospects, and in fact, you must include an unsubscribe process (or at least links to it) in ALL of your mailings.

E-reputation: your digital reputation, your online reputation, on all media. Subject to sudden changes, e-reputation is very difficult to assess and maintain.

ISP: Internet Service Providers.

White list: list of advertisers that are recognized for having good practices by ISPs, as reliable advertisers.

Black list: list of advertisers who have not respected the ethics of emailing and are therefore banned from inboxes by ISPs.

Complaint: can be made directly to the advertiser or to an organization. It comes from a prospect and expressed his displeasure. A complaint must always be managed immediately to find a positive outcome.


Deliverability is a complex principle. It has many effects on your campaign, but also many actions of your campaign affect deliverability. Deliverability therefore has a reciprocal relationship with email campaigns. But remember, good deliverability is also a question of adapting to new technologies, new trends, as well as new laws managing the mass emailing.

However, you are not alone in this struggle to maintain and optimize your deliverability. Mailpro lend a helping hand by offering effective tools for creating emailing, database management and data routing. Mailpro will observe with you the results by its emailing statistics. Test our deliverability by opening a free account!