Network & Email Tools

DNS and email authentication tools that run real queries or generate real records — not just static explanations.

DNS Lookup Tool

Look up A, AAAA, MX, TXT, CNAME, NS, SOA and CAA records for any domain, queried live via DNS over HTTPS.

SPF Record Generator

Build a valid SPF TXT record with includes, IP ranges, and a DNS lookup count warning.

SPF Record Checker

Check an existing SPF record for syntax problems and a recursive DNS lookup count.

DMARC Record Generator

Build a valid DMARC TXT record — policy, alignment, reporting addresses, and rollout percentage.

DMARC Record Checker

Check an existing DMARC record, see it decoded in plain English, and catch common gaps.

IP Blacklist / DNSBL Checker

Check an IPv4 address against Spamhaus, Barracuda, SpamCop, SORBS, UCEPROTECT and more.

More tools in this section are planned — including a DKIM lookup. All tools here run entirely in your browser or query public resolvers directly; nothing you enter passes through or is logged by CalcLoop's servers.