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