Mail Administration

See also:

• automatic discovery of mail server settings for clients

see also: DNS

Allow server in A record, allow server in MX record, disallow all others.

v=spf1 +a +mx -all

put into TXT record _dmarc.example.com:

v=DMARC1; p=none; rua=mailto:postmaster@example.com; ruf=mailto:postmaster@example.com;

https://dmarcian.com/dmarc-tools/

more information: Postfix Queue Management

Office Blacklist: https://sender.office.com/

Outlook.com anti-spam mechanisms: https://sendersupport.olc.protection.outlook.com/pm/services.aspx

SNDS: https://sendersupport.olc.protection.outlook.com/snds/index.aspx

If you send through an SMTP Smart Relay through Office 365, you might need to include the IP address you're sending from (not only the Microsoft servers, but your own SMTP server) in the SPF records.

• Internet.NL – tests for IPv6, DNSSEC, DMARC, DKIM, SPF and STARTTLS
• SSL-Tools – checks if mail server uses STARTTLS for mail delivery
• MX Toolbox – checks mail deliverability (DMARC, SPF, DKIM)
• Is Not Spam – SPF, Sender-ID, DomainKeys, DKIM, SpamAssassin Check