Spam placement is almost always an authentication or reputation problem, not a content problem. Three DNS records fix the first; how you send fixes the second.
SPF: who may send as you
A single TXT record listing every service allowed to send mail using your domain. You may only have one SPF record — if you use HostLift email plus a newsletter tool plus a CRM, all three go in the same record.
DKIM: a signature on every message
A cryptographic signature added by the sending server and verified against a public key published in DNS. It proves the message was not altered in transit and genuinely came from an authorised sender.
DMARC: what to do when checks fail
A policy record telling receiving servers whether to ignore, quarantine or reject unauthenticated mail, and where to send reports. Start with p=none and monitor reports for two weeks before tightening to quarantine.
Habits that hurt
- Sending bulk newsletters from the same domain and IP as your transactional mail.
- Buying or scraping lists. A handful of spam complaints undoes months of good reputation.
- Ignoring bounces. Repeatedly mailing dead addresses is a strong negative signal.
- Sending from an address that cannot receive replies.