How to deal with SPAM

The sending of unsolicited e-mails (commercial communications) is a relatively topical topic today. In view of the large number of such e-mails, technical solutions are emerging that seek to reduce anonymous distribution of spam. Unfortunately, these antispam tools, filters, and settings can sometimes result in trouble-free and expected email as SPAM (it always depends on the recipient's mail server's specific configuration and how it handles spam).

These settings only apply if you have set your own email address on your own domain as the sender of emails from the system! Custom email addresses on domains like,, etc. cannot be influenced by DNS settings. To set DNS parameters you must have access to the DNS administration of the specific domain.

Keep in mind that setting DNS parameters for a domain can affect the availability of your website, the functionality of email addresses, etc. Settings should always be made by the domain administrator and with the specific implications of each setting in mind.

Configuration of SPF

So if you run a reservation system from which you send (in your name / address) emails to your customers with a booking confirmation, booking notification, etc., it is good to remember that in some cases these emails may end up in SPAM. One solution that can help reduce the risk of non-delivery of e-mail messages is to use the SPF (Sender Policy Framework) configuration. By correctly setting up your domain you will tell the world (mail servers) that specific mail servers have the right to send e-mail messages on your behalf, ie with your address. Because all reenio emails are sent through a dedicated, dedicated cloud-based cloud solution, you need to make sure that emails with your address are trusted, even if they are sent from our servers.

SPF is set in the DNS configuration of your domain, ie the domain that corresponds to the e-mail address set in the system. As this is a significant intervention (incorrect settings can affect sending emails with your address), we strongly recommend to leave this setting to your IT administrator, who takes care of your domains! Within the SPF settings, it is necessary to create / edit the TXT record in the DNS settings of the domain to include the domain

Example of possible (with respect to already existing settings) TXT record value

v=spf1 a mx ~all

If you are interested in SPF and want to know how this way of protection works. how to set it up correctly, we recommend starting with How SPF works.

Configuration of DMARC

As part of the comprehensive setup of your domain that you use as a sender of email messages from the system, it is very useful to set the DMARC parameter as well. Again, this is a parameter managed within the DNS settings of your domain. The DMARC mechanism is used to specify what and how to do if spam using the domain is intercepted.

Example of possible TXT record settings

v=DMARC1; p=quarantine;

Configuration of DKIM

The DKIM technology provides the ability to authenticate emails being sent, from the perspective that the sender is indeed the one who is authorized to send emails with the given sender address. This is a principle that uses signing of sent messages with specific keys. In the case of a DKIM setup, parameters are set within DNS that specify where the authentication keys for a given domain can be found. These keys are provided within the system by us or through the services we use to send the emails. To set up DKIM correctly, follow the instructions provided in the administration, which are specific to each individual sender domain.

Settings - General Settings - Email - Email Address Verification - extended verification (DKIM)

SMS messages as a suitable supplement

The issue of sending e-mail messages and protecting against spam is very complex and still evolving. This will not always ensure that emails reach all recipients through all protection, filters, and security settings (especially if the recipients have email running on corporate networks and systems). That is why the reenio reservation system also offers a second form of direct communication with customers by means of SMS messages. By combining both approaches and using two communication channels (e-mail and SMS) you will be sure that all necessary information will reach your customer!