Tools
Check routing, names, and public DNS before you change MX.
Live lookup pages query public resolvers. They show published records. They do not prove inbox placement, SMTP credentials, or a private alias route. Use Troubleshooting when you need the scored MailerZ readiness scan.
Email Routing Lab
Simulate inbound forwarding and outbound SMTP for a sample domain, alias, and destination.
Disposable email checker
Screen an address or domain for known disposable providers and public MX signals. It does not prove a mailbox exists.
Alias name generator
Create role-based or opaque alias ideas in the browser. Nothing is uploaded.
Full DNS diagnostic
Scored public MX, leftover routes, SPF, DKIM, and DMARC check for a real domain.
Public DNS lookups
MX lookup
Query public MX records to see which mail exchangers currently receive mail for a domain.
Leftover MX checker
Check whether old Google, Microsoft, or hosting MX records are still published beside or instead of the intended route.
SPF check
Read the public SPF TXT record and flag missing, duplicate, or oversized policies.
SPF lookup
Fetch the public SPF record for a domain so you can compare it with the value in your dashboard.
DKIM lookup
Resolve selector._domainkey for a domain and show the public DKIM TXT or CNAME.
DMARC lookup
Read _dmarc TXT and check for a single policy with a valid p= value.
DNS lookup
Query A, AAAA, MX, TXT, NS, CNAME, and SOA for a domain from public resolvers.
PTR lookup
Convert an IPv4 address to in-addr.arpa and return the published PTR name.
TXT lookup
Fetch root TXT records, including verification, SPF, and other published strings.
SOA lookup
Read the start-of-authority record for serial, refresh, retry, expire, and minimum TTL.
What public DNS can and cannot prove
A public DNS lookup shows the MX, SPF, DKIM, and DMARC records resolvers currently publish. IETF RFC 5321 describes how sending servers use MX to choose a destination. RFC 7208, RFC 6376, and RFC 7489 define SPF, DKIM, and DMARC. A green lookup does not prove inbox placement, SMTP credentials, or a private alias route.