Mail Transfer Agent Strict Transport Security ( MTA-STS) is a new standard that aims to improve the security of SMTP by enabling domain names to opt into strict transport layer security mode that requires authentication and encryption.Īll these records except MTA-STS can be generated via Power DMARC Toolbox. Some fields are not necessary but nice to have. The handy SPF record online generator can be used.

relayer_name – optional external mail relay server name.

Our DNS record will look like a mx include: relayer_name -all Sender Policy Framework ( SPF) is an email authentication standard that checks the sender’s IP address against a list of the domain owner’s authorized IPs to validate incoming email.

TTL has the same meaning as in the previous paragraph.

public_key – our public key encoded by base64 algorithm.

‘mysrv’ that will be used in our mail server application.

selector – self-chosen identifier e.g.

Openssl.exe rsa -in private.key -pubout -outform der 2>nul | openssl.exe base64 -A > It can be generated by an online tool like Power DMARC Toolbox – DKIM Record Generator, or by OpenSSL commands (provided for Windows): The receiving server verifies it with a public key to ensure the email hasn’t been tampered with.

TTL can be set to any preferable value and the lowest value is used to apply DNS changes as soon as possible while setting up our own email server.ĭomainKeys Identified Mail ( DKIM) is an email security protocol that attaches an encrypted digital signature to an email.

Priority is used when our domain has more than one mail server.

if our domain is, the mail server is, then the DNS record for will min

So, we need to point domain name of our self-hosted mail server that will process mail of our main domain. It can be easily checked by your IP via a special online checker like this, or Windows’s ‘nslookup’ tool and ‘host‘ command in UNIX-based systems.Ī mail exchanger record ( MX) specifies the mail server responsible for accepting email messages on behalf of a domain name. You can ask your hosting or internet service provider to set up it to your public domain name. Further, the back DNS record (named PTR) must point our IP to the domain name of our own mail server.

How to setup collabora online server