- The Email-address
- A basket full of seeds
- What has to be thrown away
- What exactly is checked during address validation?
- SMTP verification (to find hard bounce addresses)
- Spam Trap Check (Spam traps are removed)
- Gray listing detection (To prevent grey listing during validation)
- “One-way” email address check (One-way addresses are deleted)
- Domain Check (Checks whether the domain is active and valid)
- Email syntax check (Structure and completeness of the e-mail address)
- Catch-all domains – A special case
- Challenges in validation
- The Guarantee – Taking the example of Bancomail
It sounds banal, it seems banal, it is banal … there are countless topics on the subject of email marketing, scientific papers, conjectures, theories, well-intentioned advice and tips – but there is one element in this game that is and should be without doubt the basis of all considerations, as banal as it is … the email address.
The email address as a seed, with the hope that a tender little tree will grow from the seed, which, after much care and affection, will eventually develop into a stately tree that will one day bear juicy fruit and thus yield a rich harvest.
At first glance this seems a strange comparison, but at second glance there are countless parallels.
So let’s start with our seeds … the email addresses, because without vital seeds, the chances of a germ, or a tender little plant, are slim or even completely hopeless.
A basket full of seeds
In spring, when the planting season begins and the fields are tilled, it is worth taking a closer look at the seeds. A look into the basket with the seeds already gives an idea of whether growing plants can actually be expected after sowing.
In our case, the basket is the database with all the email addresses that are to be used to build up, at best, profitable customer relationships.
But as in the orchard, (machines for gardening you will here), it pays not to rely on luck alone, because in the worst case it means that nothing but weeds grow in our fields and we have invested time and effort in vain, when it would have been so easy to analyse the seeds in winter and not sow them unchecked.
This all seems understandable and reasonable for the seeds and leads us to expect a higher yield.
Exactly the same applies to the email addresses in a database for email marketing. Often a useless collection for email addresses, more or less sorted, and unfortunately rarely sufficiently well controlled.
Control in this case means validating the addresses. Validation, checking whether it is a usable, functional address, is the solution here to sift out the bad addresses and ensure high quality.
What has to be thrown away
With bad seeds, the harvest is lost, with faulty email addresses, there are several categories of negative consequences.
In the best case, it is an address that is simply outdated and no longer in use. In this case, the damage caused by the use is relatively minor. Unnecessary effort has been invested in the mailing, without a return, or even the chance of one.
A much more unpleasant form of error would be a “spam trap” address, which would have far-reaching negative consequences if sent. If this address is used, one’s own IP address would end up on a blacklist and thus all ambitions to build up a functioning email marketing would be thwarted or made more difficult.
What exactly is checked during address validation?
SMTP verification (to find hard bounce addresses)
This check verifies to what extent the inbound SMTP server is able to accept incoming sessions and also responds to requests.
Spam Trap Check (Spam traps are removed)
Spam trap addresses are used by ISPs (Internet Service Providers) or block list companies to detect spammers and ultimately block them by “black listing”. Here, too, there are different categories. Many of these addresses appear to be regular email addresses, but they are invalid email addresses that have been transcribed and are difficult to identify. Others are relatively obvious and easy to spot because of spelling mistakes or their choice of words.
The detection of spam traps requires in-depth analysis and the application of specific techniques to identify these addresses. One of the strategies used is the analysis of email address reaction metrics. Another common technique is cross-checking with known spam trap lists or databases of invalid email addresses. These lists, such as ‘honeypots’ or ‘sinkers’, contain addresses specifically created to attract spammers.
Anyone who sends emails to these spam traps is demonstrably doing so without prospecting (identification of potential customers) of the recipient, and this is then the corresponding indicator and the basis of which one is placed on a blacklist.
Gray listing detection (To prevent grey listing during validation)
“Grey-listing” was developed as a measure to prevent spam, whereby an email is temporarily rejected by the receiving server if the sender is questionable. The system then informs the sending server that the email should be resent in order to actually deliver it.
Since spammers usually do not send the same email more than one time shortly after another, unwanted emails are filtered out in this way and do not reach the inbox.
For email validation, this means a hurdle that must be overcome, because no clear feedback can be expected with a single delivery attempt, which means that no statement can be made about whether the email address to be checked is actually valid. This can only be ensured by a renewed delivery attempt, which then confirms the status of the address to be validated.
“One-way” email address check (One-way addresses are deleted)
“Disposable” (one-time or temporary use) email addresses are certainly not the rule, but they do exist and should be detected and removed from the database. There are two main reasons for this.
Firstly, it is obviously an unnecessary effort to “waste” your marketing activities on this type of address, and secondly, these addresses can also generate hard bounces (undeliverable emails), which negatively affects the sender’s reputation. This also happens when emails can be sent and delivered but are never opened and read.
Domain Check (Checks whether the domain is active and valid)
When checking the domain, the MX entry (Mail Exchange) in the Domain Name System is determined for the corresponding domain.
The MX record is critical because it specifies which mail server handles the emails for a particular domain. Without a valid MX record, emails sent to a domain may not be delivered correctly.
It is important to note that a domain may not have a valid MX record for a number of reasons, such as technical problems or an inactive domain. If the MX record of an address does not exist or is invalid, obviously no email should be sent to it.
Email syntax check (Structure and completeness of the e-mail address)
The syntax check verifies whether the structure of the email address is correct according to RFC 5322 (Internet Message Format) and RFC 5321(Simple Mail Transfer Protocol). The first part of the address, with a length of up to 64 characters, may consist of Latin letters, numbers and some special characters, whereby upper and lower case are permitted. This is followed by an “@” (at) and then the second part of the email address, which indicates the name of the domain and can consist of up to 253 characters.
Catch-all domains – A special case
Catch-all domains are a special case that must not go unmentioned, because these domains basically accept all incoming emails, regardless of whether the email address used is incorrect or even if there is no real recipient.
Due to this procedure, there is no feedback from the receiving server, neither a positive nor a negative feedback is given, which means that there are practically no clues about the whereabouts of an email. A 100% statement in the context of validating email addresses cannot be made and the status remains unknown.
The maximum result that can be achieved here is to ascertain whether it is one of the catch-all domains.
Although sending emails to catch-all domains is not the optimal choice for an email marketing campaign, it is important to emphasise that, when handled correctly and if in small numbers, they can still bring benefits without negatively impacting deliverability. Sending to these addresses allows you to expand the reach of your campaign and not miss opportunities. By maintaining an accurate and balanced segmentation of email addresses, you can make the most of the potential of email marketing campaigns.
Challenges in validation
Due to the fact that there is no uniform procedure among the different email providers, the validation process can become a challenge, as many different procedures have to be taken into account. Catch-all domains in particular contribute to this, which we have already described here, and so in the end a residual risk remains, even if it is small. When buying email lists, you should thus definitely pay attention to various quality features and one of these is the validation of the email addresses by the supplier.
To further minimise this small risk for the customer, the database provider should offer a guarantee and provide a replacement or credit for records that do not work.
The Guarantee – Taking the example of Bancomail
If, despite careful selection, testing and validation, bounces do occur, a complaint can be made to Bancomail within 60 days of the database being delivered. This period is sufficiently long to allow enough time for preparation, implementation and evaluation.
Bounces can be sent to Bancomail, which triggers the timely checking process. If it is then confirmed that the email addresses concerned were incorrect, Bancomail creates a voucher for a future purchase, or a credit note, depending on the customer’s wishes.