DMARC Record Creator
Create DMARC records for spoofing prevention, ready to paste into DNS
Features
Generate by selecting options
Create the hostname and value for DNS pasting on the spot
Display 3-stage deployment steps
Confirm the current configuration stage on screen
Verify guideline requirements
Check if you meet Google and Yahoo! sender requirements
Process only in browser
Your entered domain and addresses are not transmitted
How to Use
Enter domain name
Enter your email sender domain in the input field
Select policy and report destination
Choose a policy from 3 options and enter the aggregate report destination
Adjust advanced settings
Specify application percentage, alignment strictness, and subdomain policy as needed
Copy and register in DNS
Copy the hostname and value, then register as a TXT record
Use Cases
Initial setup for guideline compliance
Create a record with monitoring-only policy and start operations
Gradual policy strengthening
After reviewing reports, upgrade policy to quarantine or reject
Bulk setup for multiple domains
Design and production agencies create separate records for customer domains
Different policy for subdomains
Apply different handling to mail from subdomains only
Knowledge Base
What is DMARC
DMARC is a mechanism that allows domain owners to declare in DNS how to handle emails that impersonate their domain. It uses SPF and DKIM authentication results to tell receiving servers how to handle mail that fails authentication.
- SPF：SPF is a mechanism that lists servers authorized to send email for a domain in DNS.
- DKIM：DKIM is a mechanism that attaches a digital signature to emails, allowing receivers to verify the signature using the public key in DNS.
Differences between 3 policies
The policy (p tag) instructs receiving servers how to handle mail that fails authentication. There are 3 levels: none (no action), quarantine (move to spam folder), and reject (do not accept).
- none：none is the initial stage where you only receive aggregate reports without changing mail handling.
- quarantine：quarantine is the stage where you request that mail failing authentication be moved to the spam folder.
- reject：reject is the strongest stage where you request that mail failing authentication be rejected before delivery.
Hostname and main tags
DMARC records are registered as TXT records with the hostname that adds _dmarc. before the target domain (example: _dmarc.example.com). The value starts with v=DMARC1 and tags are separated by semicolons.
- rua：rua is the tag that specifies the address to receive authentication result aggregate reports, written with mailto: prefix.
- pct：pct is the tag that specifies the percentage of mail to apply the policy to, using a value from 1 to 100, with a default of 100.
Safety and Privacy
Runs entirely in your browser
Your input data is processed only within your browser and is never sent externally.
Processing only in your browser
Record assembly is processed entirely within your browser, and input data is not sent to any server.
Communications encrypted with HTTPS
Page loading is also encrypted by TLS, and content cannot be read by third parties.
No transmission to third parties
Input content is not sent to external services such as ad networks or trackers.
No automatic saving of results
Entered domain names and email addresses and input suggestions are not stored on the server.
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Updates
- update #251
Added a tool to create DMARC records for spoofing prevention
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