Sender Policy Framework (SPF) provides means to specify mail servers which are entitled to send messages from you domain.
To be SPF-compliant, an email sender publishes one or more DNS records that establish the sending domain's identity. Usually, these DNS records are specified as TXT (text); they identify a set of hosts that are authorized to send email. After these DNS records are created and published, ISP's can authenticate a host by comparing its IP address with the set of IP addresses specified in the SPF record.
For more information on SPF please refer to RFC 4408.
Domains with Preexisting SPF Records
If your "From" domain already has an SPF record, then you will need to add the following rule to it:
"mx:mx.ecwid.com include:spf.mtasv.net include:servers.mcsv.net"
If you have an existing SPF record, then you must add this rule - otherwise, ISP's that examine the "From:" headers might reject email that Ecwid sends on your behalf.
Adding a New SPF Record
If your "From" domain does not have an SPF record, we recommend that you add one to ensure that ISP's do not reject your email. The following is an example TXT record that you can publish to enable SPF:
"v=spf1 a mx mx:mx.ecwid.com include:spf.mtasv.net include:servers.mcsv.net ~all"