Email marketing: three DNS records before your first campaign

The three records that decide whether you are spam

All three live in your domain's DNS and all three are free.

• SPF lists which servers are allowed to send mail using your domain name.
• DKIM stamps each message with a cryptographic signature so the recipient can confirm it really came from you and was not altered in transit.
• DMARC tells the recipient what to do when the first two fail: nothing, send to spam, or reject outright.

Google requires senders to have at least one of SPF or DKIM, and is stricter still for bulk senders. With neither, your mail is not delivered at all. It does not even go to spam.

The mistake we made, and you probably have too

The domain rgb.ir has an SPF record and it is correct. It has a DMARC record too, set to quarantine. Gmail rejected our mail anyway.

The reason: the mail server introduces itself as mail.rgb.ir and the envelope sender domain is therefore that subdomain. Gmail went looking for an SPF record on mail.rgb.ir and found nothing, because SPF is not inherited. A record on the root domain does nothing whatsoever for a subdomain.

We had a second fault as well, not fatal on its own but just as common: the reverse DNS record for the server IP points at a different hostname. The server says it is one thing and the network says it is another. Strict recipients treat that mismatch alone as reason enough to refuse.

Both are being fixed and we will publish the before and after once they are. We put them here because reading a real error from a real server teaches more than any tutorial list.

Three things that bite harder in some markets than others

Environment matters and the international guides rarely mention it:

• IPv6 with no reverse record. If your server has IPv6 and no PTR was configured for it, mail may leave by that path and be rejected while the IPv4 path is fine. It is hard to diagnose because some messages arrive and some do not. The quick remedy is to disable IPv6 for mail.
• Bulk sending platforms you cannot reach or pay for. Where the well known global services are unavailable or will not accept your payment method, the choice narrows to a regional provider or your own sending server with all the responsibility that carries.
• IP reputation. On shared hosting your IP address is shared with dozens of other sites. If one of them sends spam, the shared reputation degrades and your mail is caught with it.

The third is a good reason to separate bulk sending from your website server. If you are on a server shared with other sites, running a campaign from there is pure risk.

Three technical mistakes that kill a campaign before it starts

Sending HTML with no plain text alternative earns a spam score from most filters, and most tools will not generate the text part unless you ask. Sending from a no-reply address on a different domain fails authentication outright, because the sending domain has to be the one carrying SPF and DKIM. And trusting your tool's success message proves nothing: when a plugin says the mail was sent, it means the mail was handed to the mail server. Real delivery shows up in the server log. We have made a habit of it: after any change, read the log rather than the success banner.

The order we recommend

Before the first campaign, in this sequence:

• Write SPF on the root domain and on every subdomain that actually sends mail.
• Enable DKIM, then send a test to a Gmail account and read the headers to confirm it passes.
• Set DMARC to reporting first, read the reports for a few weeks, then tighten it.
• Send a test to Gmail, to a corporate mailbox and to a regional provider, and check all three.
• Only then, the list and the copy.

Do not skip the third step. DMARC set to reject, with SPF or DKIM incomplete anywhere, destroys your own mail as well, including password resets and invoices.

And then the marketing part

Once the technical side is right, two things matter most and neither is the copy. First, a list you gathered yourself. A purchased list is both ineffective and a fast way to burn your domain reputation. Second, an obvious unsubscribe link. Someone who cannot unsubscribe presses the spam button instead, and that one goes straight at your reputation.

Email earns its place in combination with other channels rather than alone. Which channel comes first for your business is a digital marketing strategy question with no universal answer. And if you do not yet have a site for the emails to link to, the order is reversed: the website first, then the channel.

One security note that rarely gets said: an unprotected newsletter signup form fills with fake bot addresses within weeks. Those addresses later raise your bounce rate and damage your reputation. Protecting your forms is part of this job, not a separate topic.

Common questions

What is email marketing?

Sending messages to a list of people who agreed to receive them, to sell or to maintain a relationship. The consent is the whole difference between it and bulk sending; without it, what you are doing is spam.

What are the drawbacks?

Heavy dependence on list quality, high sensitivity to technical configuration, and the fact that damaging your domain reputation is quick while repairing it takes months. Unlike paid clicks, a mistake here has lasting effects.

Which email marketing service is best?

Start from availability and payment rather than the feature list. Before choosing, ask whether they configure DKIM on your own domain and whether they report real delivery and bounce figures.

How do I tell whether my mail goes to spam?

Send a test to a Gmail account and open the original headers. If anything other than pass appears next to SPF or DKIM, your problem is technical rather than editorial.