Port233 Service
Microsoft 365 email DNS setup
Set up and review Microsoft 365 DNS records so business email can send, receive, and authenticate properly.
Email DNS records that matter
Microsoft 365 email depends on correct MX routing, SPF sender authorization, DKIM signing, and DMARC policy alignment. Security upgrades such as MTA-STS and TLS-RPT can improve encrypted transport and reporting after the core records are healthy.
Port233 can help review the existing records, spot duplicate or missing values, and create a clean sequence for changes.
When this support is useful
This is useful after a migration, when messages fail authentication, when SPF has become too broad, or when a domain needs to move from DMARC monitoring to quarantine or reject.
Common questions
Which Microsoft 365 DNS records affect deliverability?
MX, SPF, DKIM, and DMARC are the core records. MTA-STS and TLS-RPT are useful additional records for encrypted mail transport and reporting.
Can Port233 help move DMARC from monitoring to enforcement?
Yes. Port233 can help review legitimate senders, align SPF and DKIM, and plan a controlled move from p=none toward quarantine or reject.
Can one domain have more than one SPF record?
No. A domain should publish one SPF TXT record. Multiple SPF records can cause SPF evaluation failures.