Friendica Social Network

Jan Schaumann 1 year ago • mastodon (AP)

Every so often, I need to chase down some aspect of email validation (#SPF, #DMKIM, #DMARC, ...). This involves a number of #DNS records and queries, but I may forget just which ones. So here's a quick #SMTP/DNS cheatsheet:

Table:
Record / Type Example
-------------------------------------------
MX dig +short MX example.com
SPF dig +short TXT example.com | grep spf
DKIM dig +short TXT selector._domainkey.example.com
DMARC dig +short TXT _dmarc.example.com
MTA-STS dig +short TXT _mta-sts.example.com
curl https://mta-sts.example.com/.well-known/mta-sts.txt
TLS-RPT dig +short TXT _smtp._tls.example.com
DANE dig +short TLSA _port._tcp.example.com
BIMI dig +short TXT default._bimi.example.com

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