Free Postmaster Tools

Free tools for postmaster including SPF analyzer, DKIM analyzer, DMARC analyzer, SPF and DMARC wizard, DNS lookup, IP and CIDR converter and more.
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SPF Analyzer
Enter domain name to find out which servers are authorized to send email on behalf of that domain.
Use SPF Analyzer
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DKIM Analyzer
Enter domain name and selector to check current DKIM record of that domain.
Use DKIM Analyzer
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DMARC Analyzer
Enter domain name to check current DMARC record of that domain.
Use DMARC Analyzer
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DNS Lookup
Perform a DNS lookup to check a DNS record against multiple name servers located in different parts of the world.
Use DNS Lookup
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CIDR Notation to IP Range
Convert CIDR notation (e.g. 10.0.0.0/24) to IP address range.
Convert CIDR Notation to IP Range
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IP Range to CIDR Notation
Convert IP address range to CIDR notation.
Convert IP Range to CIDR Notation
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DMARC Wizard
Create a DMARC policy for your domain.
Use DMARC Wizard
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SPF Wizard
Create a SPF record for your domain.
Use SPF Wizard