spf

http://www.openspf.org/SPF_Record_Syntax

Here is some SPF examples

v=spf1 include:_spf.google.com a a:server10.hosthat.com ip4:147.243.1.48 -all

DMARC record

_dmarc.yourdomain.com TXT  "v=DMARC1; p=none"

If you need to reject email, add

v=DMARC1; p=reject; pct=100; rua=mailto:YOU@YOUR-DOMAIN.COM

If you just need report, add

v=DMARC1; p=none; rua=mailto:YOU@YOUR-DOMAIN.COM; ruf=mailto:YOU@YOUR-DOMAIN.COM;

YOU@YOUR-DOMAIN.COM – this can be any email address where you need DMARC reports sent to. Mail providers sent you report on this, that you can review to make sure no one sending spam mails.

SPF Tools

http://www.kitterman.com/spf/validate.html
http://spf.myisp.ch

Cpanel Server Block Incoming SPF Failed Mails