DNS (Domain Name System)
DNS (Domain Name System) is the “phone book of the internet”: it translates domain names such as circle.gmbh into the technical addresses of the servers running website and email.
A domain’s DNS settings determine where requests go: which server delivers the website, where emails are delivered and which services may send emails on behalf of the domain.
For email delivery, certain DNS records are particularly important: SPF, DKIM and DMARC prove to other mail servers that messages really come from the company. Without them, emails land in spam more often.
DNS changes do not always take effect immediately because records are cached. This should be planned for when moving a website or email.
What to look out for
- Document where DNS settings are managed and who has access.
- Set up SPF, DKIM and DMARC for the email domain.
- Back up all existing records before a move.
- Plan moves for quiet times and account for caching.
- Remove records that are no longer used.
Common mistakes
- During a website move the email records are overwritten — emails stop arriving.
- No SPF, DKIM or DMARC — invoices and offers land in spam.
- Nobody knows anymore where DNS settings are managed.
Frequently asked questions
Often the DNS records SPF, DKIM and DMARC, which mail servers use to verify the sender, are missing or wrong. Content and the sending server’s reputation also play a role.
Often a few minutes to hours; depending on caching it can take longer until all users see the change.