FAQ

Here you can find common questions about the "Sending domains" navigation item.

Sending domains are required to ensure that your emails can be sent correctly from a technical perspective. The right settings create the basis for reliable delivery.

SPF defines which servers are allowed to send emails on your behalf.

Receiving mail servers check whether the sender is authorized to send emails through a domain. If not, your emails may be classified as spam and your reputation can suffer.

When you use Inxmail, the physical sending process runs through Inxmail mail servers. Authorize Inxmail via a DNS record so that sending through your domain works correctly.

DKIM signs your emails so that it remains verifiable that no one has changed the mailing content.

The DKIM signature is stored in the email header and is based on asymmetric encryption (public/private key).

A valid DKIM signature confirms:

  • that the email content was not tampered with on the way to the recipient

  • that the header fields were not changed

  • that the sender owns the domain or is authorized to send through it

When you use Inxmail, the physical sending process runs through Inxmail mail servers. By default, the sender domain inxserver.com is used, which is displayed in many email clients (for example Outlook, Hotmail, or Gmail).

All emails that you send with Inxmail are automatically signed with DKIM, initially through the Inxmail domain inxserver.com.

Some receiving mail servers rate it negatively if the DKIM signature and the visible sender domain do not match. That is why you should add your own sender domain for DKIM via DNS records so that the DKIM signature matches your sending domain.

Your mailings will still be sent through the Inxmail sending servers.

Without correctly configured DKIM signing, you cannot send emails with Inxmail.

Use DMARC to define how emails are handled if they fail SPF and/or DKIM checks.

With DKIM and SPF, email providers check whether emails actually come from the stated sender and whether the sending mail server is allowed to send emails for a specific sender domain.

However, neither of these methods tells the receiving mail server how to proceed if a check passes or fails. DMARC closes this gap. The DMARC policy lets you define the following options for emails that fail DKIM or SPF checks:

  • "none" (= regular email delivery)

  • "quarantine" (= move the email to the spam folder)

  • "reject" (= the email is not delivered)

Use a DNS record to define which option applies to your sender domain.

Note: DMARC requires domain alignment that passes SPF and DKIM checks.

To set up your sending domain correctly, your domains need to be aligned.

Domain alignment

A basic requirement for DMARC is that your domains are aligned:

  • visible sender address (FROM)

  • technical sender address in the email header (MAIL FROM / Return-Path), which is relevant for SPF

  • the domain specified in the DKIM header

Full domain alignment

In addition, the domains of the URLs

  • for link tracking
  • for website links

should also match the sender domain.

See: Use your domain

Outside Inxmail: Do not configure BIMI in the Sending domains navigation item. Get in touch with your Inxmail contact person or if you need help with the setup.

With BIMI, your recipients can recognize your authenticated emails directly by your company logo in their inbox.

Whether your logo is actually displayed depends on your domain settings and the receiving email provider. Many providers require a Verified Mark Certificate (VMC). Contact your Inxmail contact person or for more information.

At https://bimigroup.org/bimi-infographic/, you can find an overview of the mailbox providers that support BIMI now and in the future. The BIMI Group updates this overview continuously.

An internet address (or URL) consists of the following parts:

 

A subdomain is a domain in which a domain name is placed in front of the organizational domain and separated by a dot.

  • Main domain: example.com

  • Subdomain: subdomain.example.com

For technical and performance reasons, you can use up to 50 domains per XPRO tenant, either as a sending domain or as a redirect URL. Get in touch with us if that is not enough.

If you want to use a very large number of domains or redirect URLs, get in touch with us.

We recommend setting up a subdomain that you use exclusively for sending emails via Inxmail. This helps you avoid unwanted effects on your main domain and your everyday email traffic.

You also need to use the subdomain that you set up in "Sending domains" later in your sending settings. Only then do the settings from "Sending domains" take effect.

In Newsletters & campaigns, use it in your list settings. In Transactional mails, use it in your mailing settings and, if needed, in your source systems.

Setup differs for each domain host. Ask your IT team to handle the setup for you and contact your domain host if you need help.

It is technically possible to use existing domains, but we do not recommend it.

As soon as you authenticate an existing subdomain in Inxmail, the old system must stop sending any emails through it. You can also run into issues with links in the old system, for example the unsubscribe link.

A switch also means that mailbox providers suddenly receive familiar emails from a new sending source. This can lead to delivery issues.

We strongly advise against using your main domain for sending with Inxmail. Otherwise, reputation losses from your sending can affect the core of your company and brand.

From a purely technical perspective, you can send through your main domain by using Main domain or subdomain via alias.

We still advise against this option because it carries a high risk of setup errors and reputation loss.

  • Intuitively, you might think: The main domain looks more trustworthy than a subdomain.

  • Technically, the opposite is often true: If you send through your main domain and also use it outside Inxmail, authenticating your mailings with DMARC becomes much more complex and much more error-prone.

    That is why we recommend creating a subdomain that you use exclusively for Inxmail. You can authenticate this subdomain easily and safely as "Subdomain with delegation" or "Subdomain via alias".

The DNS records in Sending domains let you send your emails through Inxmail servers while still authenticating and signing your emails with your own domain.

The DNS records differ depending on the option. Add the records that Inxmail shows for your option.

Adding DNS records differs for each domain host. Ask your IT department to make the change for you and contact your domain host if you need help.

Here you can see the most important differences between the different options for setting up "Sending domains".

With "Subdomain with delegation", you have the lowest long-term maintenance effort. You store DNS records once and use them to delegate the domain to Inxmail. If domain records need to change later, Inxmail makes the adjustments and you do not have any additional work.

Compared to "Subdomain with delegation", "Subdomain via alias" differs in the type of DNS records. Here, you use CNAME and TXT records. In practice, this means that you remain responsible for maintaining and updating your DNS records over the long term.

In terms of deliverability, there is no difference between "Subdomain with delegation" and "Subdomain via alias". Both options set you up well for deliverability.

Use the "Main domain or subdomain via alias" option only in absolute exceptional cases. In general, we advise against it.

Important: With "Main domain or subdomain via alias", you need to make many settings manually yourself. Only experienced IT or mail server administrators should make these changes.

If you use "Main domain or subdomain via alias", you use the same domain for different sending sources, for example newsletters, transactional mails, or everyday emails. This can lead to major reputation problems.

If you separate these mail types instead, each domain builds its own reputation and the sending sources do not interfere with each other.

If you want to work with "Main domain or subdomain via alias", you need to ensure that all systems that send emails on your behalf adhere to your deliverability standards. This process is very time-consuming and can take a long time depending on your IT infrastructure.

Conclusion: Setting up a dedicated subdomain that you use exclusively for sending emails via Inxmail is the easiest and safest way to protect your domain.

The catch-all forwarding address collects all replies sent to email addresses on your authenticated sending domain and forwards them to the forwarding address. The forwarding address therefore acts as the default reply-to address for your mailings.

You can define exceptions later if replies to specific email addresses should not be delivered to the catch-all forwarding address.

The forwarding address can be on your main domain, for example reply@example.com. It can also be on another subdomain. It just must not be on the subdomain that you are authenticating right now.

Because the forwarding address is a catch-all forwarding address, a loop would be created if the forwarding address were on the same subdomain that you are authenticating right now.

In short: The forwarding address must not be on the subdomain that you are authenticating right now so that emails to the forwarding address are delivered instead of being forwarded again.

Yes. The forwarding address must point to a real email address and an existing mailbox so that your emails can be delivered.

In the future, replies to your mailings will arrive in the inbox of your forwarding address.

Yes. You can change the forwarding address while the system is live.

By default, there is a catch-all forwarding rule. That means all versions of email addresses on your sending domain are forwarded to the forwarding address that you enter here.

If you do not want all emails to go to the forwarding address listed here, you can define exceptions later.

Setting up Sending domains is all about optimal deliverability for your emails. That, in turn, depends on your reputation as a sender.

Here you can find the most important questions and answers about reputation and reputation loss.

As a sender of emails, you can build a reputation with email providers such as Yahoo, GMX, or Gmail. Many factors contribute to this reputation:

  • Your technical infrastructure, for example SPF, DKIM, and DMARC

  • editorial quality of your emails

  • user engagement such as opens, clicks, or spam complaints

Sending domains helps you set up your subdomain correctly with the most important authentication methods in mind.

  • Use SPF so that only authorized senders can send emails from your domain.

  • Sign your emails with DKIM.

  • Use DMARC to control what should happen to mail sent from your domain if authentication fails.

  • Use BIMI so that recipients can identify authenticated mail sent from your domain at first glance by your company logo. Add your BIMI record directly with your email provider outside of Inxmail.

Set up your subdomain correctly. Then you meet all technical requirements for an optimal reputation.

  • Make sure that the content of your emails is high quality and tailored to your recipients.

  • Build a high-quality recipient list with double opt-in. Maintain your addresses, do not buy addresses, and delete bounced addresses promptly.

Examples of reputation loss include:

  • Your domain ends up on a blacklist.

  • Email providers such as Yahoo, GMX, or Gmail no longer trust you as a sender, and your emails land in spam.

In the worst case, reputation losses can lead email providers to block you as a sender so that even your regular business emails can no longer be delivered.

Effects on your regular business emails can be avoided. Take the following precautions:

  • Use the subdomain that you use in Inxmail exclusively for Inxmail and not for any other purpose.

  • Do not send your emails in Inxmail through your main domain.

  • Set up sending domains correctly.

  • Set up sending domains correctly.

  • Separate the subdomain that you use for Inxmail from your main domain and your everyday emails.

  • Do not contact recipients unless you have their consent.

  • Practice high-quality email marketing in your daily work as well.