Domain names and email deliverability — what do you need to know?
Author: Domeny.ForSale editorial team Published Updated
In brief: A good domain name alone does not ensure that messages reach the inbox. Domain and sending infrastructure reputation, correctly configured SPF, DKIM and DMARC records, and how you acquire recipients also matter. A new domain should be introduced gradually, while monitoring bounces, complaints and authentication results.
How a domain affects deliverability
Email deliverability means a message’s ability to reach the recipient’s mailbox, ideally the main inbox rather than the spam folder. Mail servers assess many signals: the domain shown in the sender field, the domains used in the technical elements of the message, the server’s IP address, the message content and recipients’ reactions.
Domain reputation is built on sending history. Factors that harm it include spam complaints, messages sent to inactive or nonexistent addresses, sudden spikes in volume and attempts to impersonate the domain. Changing email providers does not automatically remove problems associated with the domain itself.
An extension such as .pl or .com usually does not determine deliverability. Consistency in configuration and sender behaviour matters more. An unusual extension may, however, require greater caution from a business perspective if recipients do not recognise the address and are more likely to mark messages as suspicious.
SPF, DKIM and DMARC: three essential safeguards
SPF is a DNS record that identifies the servers authorised to send email on behalf of a domain. It should cover all actual senders, such as business email, an invoicing system and a newsletter platform. A domain should have one correctly assembled SPF record; creating several separate records can cause validation errors.
DKIM adds a cryptographic signature to a message. The recipient’s server checks it using a public key published in DNS. A valid signature confirms that the message was authorised by that domain and has not been altered in transit.
DMARC specifies what the recipient should do when a message does not pass SPF or DKIM checks in a way that aligns with the domain shown in the “From” field. It also allows you to receive reports on the use of the domain. It is best to tighten the policy in stages: start with monitoring, identify legitimate email sources, and only then consider sending non-compliant messages to spam or rejecting them.
For example, a company sends regular email through Microsoft 365, newsletters through an external platform and invoices through an accounting system. Before enabling a restrictive DMARC policy, the administrator should inventory all three sources, configure them in SPF or DKIM and check domain alignment. Overlooking the invoicing system could cause legitimate messages to be rejected.
One domain or separate subdomains
Separating different types of email sending through subdomains makes configuration and reputation analysis easier. Employee correspondence can use the main domain, while marketing messages can use a subdomain such as news.example.pl. System notifications can be sent from another subdomain, such as notify.example.pl.
This separation limits the spread of problems between channels, but does not provide complete isolation. Email providers may associate a subdomain’s reputation with its parent domain. A separate domain used exclusively for bulk email is not a simple solution either: it may look unfamiliar to the recipient and requires building a reputation from scratch.
The sender’s address should be clear and consistent with the brand. Domains similar to the main one, deliberate misspellings or arbitrary variants can reduce trust and resemble phishing.
How to start sending from a new domain
A new domain has no established history, so you should not start with a large campaign sent to your entire contact list. A safer procedure includes:
- configuring SPF and DKIM and enabling DMARC in monitoring mode;
- sending tests to mailboxes at several popular providers and checking message headers;
- starting with active recipients who expect to hear from you;
- gradually increasing volume without sudden spikes;
- removing addresses that generate permanent bounces and analysing complaints;
- tightening DMARC after confirming all legitimate sending sources.
“Warming up” a domain will not fix a poor contact list. Purchased lists, a lack of the consent required for a particular type of communication, and difficulty unsubscribing from a newsletter increase the risk of complaints regardless of the technical configuration. Questions about the legal basis for marketing and the wording of consent requests must be confirmed with the person responsible for legal compliance.
What to monitor after launch
The most useful information comes from DMARC reports, bounce messages, the rate of permanent address errors and complaints reported through available email provider tools. You also need to monitor domain expiry, access to the DNS control panel and unauthorised record changes. The registrar account and DNS service should be protected with strong multi-factor authentication.
The requirements of major email providers may change and depend on the scale and type of email being sent. Before launching a campaign, check the current documentation for your mailing platform and your recipients’ mailbox providers.
The first practical step is to list all systems that send email from the company domain. Only then can you correctly assemble SPF, implement DKIM and configure DMARC without blocking legitimate messages.
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