what is a SPF (type 99) record and who do I implement?

[Security Admin (NetSec)]

Struggled to find anything explicit on this subject via google to no avail.  Best Explanation I could find was http://www.enyo.de/fw/software/exim/spf-update.html#6

Currently hosts file looks like:


Mydomain.com       172800  IN TXT  "v=spf1 mx -all"
Mydomain.com       172800  IN SPF  "v=spf1 mx -all"
Mydomain.com       172800  IN MX   10 Mail.Mydomain.com
Mail.Mydomain.com  172800  IN A    vvv.xxx.yyy.zzz


Is this correct?  FYI not using DNSSEC

Thanks in advance!

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