DNS Record Types (MX, A, TXT, CNAME)

The "key" types of DNS records for email. This section defines the most critical records: MX (Mail eXchanger), which tells the world which server accepts your mail; A (Address), which maps your server's name to an IP address; TXT (Text), the "public notes" record where you place SPF and DMARC policies; and CNAME (Canonical Name), which acts as an alias.

42 questions in this topic

What is an MX (Mail Exchanger) record? How do MX records determine where mail is delivered? How do priority levels in MX records work? How do fallback MX servers function? What happens if your MX record is missing? What’s the difference between internal and external MX records? How to test MX resolution? How does MX misconfiguration affect inbound mail? Can a domain have multiple MX records? What’s the difference between MX and A record routing? How do third-party inbound filters (e.g., Proofpoint, Mimecast) modify MX setups? How do you update MX records safely without downtime? What is an A (Address) record? What is an AAAA record (IPv6)? What’s the difference between IPv4 and IPv6 in email delivery? What happens when an A record points to the wrong IP? What’s the difference between the sending IP and domain IP? What is a TXT (Text) record used for in email? (SPF, DKIM, DMARC, BIMI) What are TXT records? Why are TXT records used for email authentication? What is a “multi-string” TXT record? What’s the 255-character limit and how to handle it? How to flatten TXT records safely? How can multiple TXT records conflict? What’s the correct syntax for quotes and spaces? How do DNS providers differ in TXT handling? What happens if TXT records overlap (e.g., multiple SPF entries)? How can TXT formatting errors break authentication? How do TXT records interact with DMARC, SPF, and DKIM? How to check TXT records from the command line? What is a CNAME (Canonical Name) record? How do CNAMEs relate to link tracking? Why do ESPs use CNAMEs for click and open tracking? How does a branded tracking domain work? What’s the difference between link CNAME and email sending domain? What happens if your CNAME isn’t verified? How do you set up link branding in ESPs? How can unbranded tracking hurt deliverability? How can broken CNAMEs cause reputation issues? How to test if your tracking domain is working? What are common CNAME misconfigurations? How do these records work together for email delivery?

Questions about DNS Record Types (MX, A, TXT, CNAME)