DNS Setup

Proper DNS configuration is essential for email deliverability. This guide covers all the records you need.

Required Records

For a domain example.com on a server at mail.example.com (203.0.113.10):

MX Record

Tells other mail servers where to deliver email for your domain.

example.com.  IN  MX  10  mail.example.com.

A Record

Points your mail hostname to your server’s IP.

mail.example.com.  IN  A  203.0.113.10

If you have IPv6:

mail.example.com.  IN  AAAA  2001:db8::1

PTR Record (Reverse DNS)

Maps your IP back to your hostname. Critical for deliverability — many receiving servers reject mail from IPs without matching PTR records.

Set this at your VPS provider (not your DNS provider). The PTR record for 203.0.113.10 should resolve to mail.example.com.

SPF Record

Declares which servers are authorised to send email for your domain.

example.com.  IN  TXT  "v=spf1 a mx ip4:203.0.113.10 -all"

a — allows the domain’s A record IP
mx — allows the domain’s MX server IPs
ip4:203.0.113.10 — explicitly allows your server IP
-all — reject all other senders (use ~all for soft-fail during testing)

DKIM Record

Vectis automatically generates a DKIM key pair when you add a domain. The DNS record is shown in the dashboard under Domains → DKIM.

default._domainkey.example.com.  IN  TXT  "v=DKIM1; k=rsa; p=MIGfMA0GCSqGSI..."

The selector is default by default. The full public key is provided by Vectis — copy it exactly.

DMARC Record

Tells receiving servers what to do with email that fails SPF/DKIM checks.

_dmarc.example.com.  IN  TXT  "v=DMARC1; p=quarantine; rua=mailto:dmarc@example.com; pct=100"

p=quarantine — failed messages go to spam (use p=none during testing, p=reject for strict enforcement)
rua=mailto:dmarc@example.com — aggregate reports sent here

Verification

After adding all records, use the Vectis deliverability checker:

# Via CLI
vectis domain check example.com

# Via API
curl https://your-hostname/api/v1/domains/DOMAIN_ID/deliverability \
  -H "Authorization: Bearer YOUR_TOKEN"

Or check in the dashboard under Deliverability — it shows a green/yellow/red status for each DNS record.

Common Issues

Problem	Cause	Fix
SPF soft-fail	Missing server IP in SPF record	Add `ip4:YOUR_IP` to the SPF TXT record
DKIM fail	Wrong selector or truncated key	Copy the full key from the Vectis dashboard
No PTR record	Reverse DNS not set at VPS provider	Set PTR at your hosting provider’s control panel
DMARC none	Policy too permissive	Change `p=none` to `p=quarantine` after testing