For the no-profit who I collaborate, with we currently have a Free Google Work Email account on domain @example.com. So, it has got some limits per day (500 messages/day).
We also own a mail server which I could use as SMTP server. To avoid Gmail (and other ISPs) spam filters I’m thinking it could be useful to setup the DNS on example.com domain in order to tell them that this “secondary” SMTP server is “official” for that domain and it is not a spammer who is spoofing the sender email address.
Someone could help me suggesting which is the best way (low priority MX record? TXT record? …)?.
Thank you very much for your help and support in advance!
searching on Google I found this website, very interesting: http://www.spfwizard.net/
I used it o create the following TXT string
v=spf1 include:_spf.google.com ip4:ab.cd.ef.gh/32 ~all
where ab.cd.ef.gh is the IP on the “secondary” mail server. Let’s cross fingers!