DNS Lookup
Look up A, MX, TXT, NS and other records, with the mail misconfigurations flagged.
About this tool
Resolves a domain's DNS records and reports what it finds, including the problems that only show up in the records themselves.
The mail ones are worth the trip. Two SPF records is the same as none — the specification says a domain publishing more than one produces a permanent error, so both are ignored and your mail starts failing authentication. An SPF record ending in `+all` authorises the entire internet to send as you. Neither shows up anywhere except in the TXT records.
Common questions
Why can I have only one SPF record?
Because the specification says so. A domain publishing two produces a permanent error, and receiving servers treat that as no SPF at all. If you need to authorise several senders, merge them into one record using include: for each.
What does +all mean in SPF?
It authorises every server on the internet to send mail as your domain, which defeats the entire purpose. Use -all to reject anything not listed, or ~all while you are still testing.
Why do I see different results than my colleague?
DNS is cached at every level, and a change takes up to the record's TTL to appear everywhere. A low TTL before a migration and a high one afterwards is the usual practice.
Does DNS affect SEO?
Only through availability and speed. A slow or unreliable resolver delays every crawl of your site. The records themselves are not a ranking signal.