(SPF, DKIM, and DMARC for Plesk + Rebel Email)
🧩 What is a TXT Record?
A TXT record (Text record) is a DNS setting that stores readable instructions for email servers and other systems.
For email, TXT records are mostly used for authentication — confirming who is allowed to send email for a domain and preventing spam, spoofing, or rejection.
There are 3 major TXT records related to email:
Type | What it does |
---|---|
SPF | Says who can send emails for the domain |
DKIM | Adds a digital signature to prove legitimacy |
DMARC | Tells receivers what to do if SPF/DKIM fail |
🔍 Real TXT Records for firstday.ca
Let’s break down your domain’s current setup:
✅ SPF – Who’s Allowed to Send
Type: TXT
Host: firstday.ca
Value: v=spf1 a mx include:relay.mailchannels.net -all
🔎 What it means:
v=spf1
= using SPF version 1a
= allow mail from the domain’s IP (A record)mx
= allow mail from mail servers in MX recordinclude:relay.mailchannels.net
= allow Rebel’s third-party sender (MailChannels)-all
= reject anything not listed above
✅ This setup says:
Only servers associated with the domain’s A record, MX record, or MailChannels are allowed to send email for
firstday.ca
.
✅ DKIM – Email Signature Check
Type: TXT
Host: default._domainkey.firstday.ca
Value: v=DKIM1; p=MIIBIjANB... (long public key)
🔎 What it means:
- DKIM (DomainKeys Identified Mail) signs outgoing email with a private key
- The receiving mail server checks the signature against this public key
- If it matches, the email is verified
✅ Your record uses Plesk’s default DKIM selector:
default._domainkey.firstday.ca
⚠️ If email is being sent through MailChannels, it also uses DKIM, and the signature is verified against this record.
✅ DMARC – What to Do with Failures
Type: TXT
Host: _dmarc.firstday.ca
Value: v=DMARC1; p=quarantine; adkim=s; aspf=s
🔎 What it means:
v=DMARC1
= DMARC is activep=quarantine
= if SPF & DKIM fail, treat mail as suspicious (spam folder)adkim=s
= strict DKIM alignmentaspf=s
= strict SPF alignment
✅ This says:
If someone spoofs
firstday.ca
and fails both SPF & DKIM, the receiving server should quarantine the message (don’t accept it into inbox).
✅ Other TXT Records
Type: TXT
Host: _domainkey.firstday.ca
Value: o=-
This one is from an older DomainKeys system (pre-DKIM). It’s harmless and safe to leave.
🛠 How to Check or Add TXT Records in Plesk
- Log in to Plesk
- Go to Domains → DNS Settings
- Look for TXT records for:
@
_dmarc
default._domainkey
- To add a new one:
- Click Add Record
- Type: TXT
- Domain: e.g.
_dmarc
or@
- TXT record: (paste the value)
🟢 Safe for agents
🔴 Do not modify DKIM manually unless advised by the mail provider
🔧 Tools to Check TXT Records (No Login Needed)
Tool | Use for… |
---|---|
MXToolbox TXT Lookup | See all TXT records for a domain |
Google Dig | Search specific TXT (e.g., _dmarc) |
Kloth.net | Run DIG queries on TXT/SPF/DKIM |
DNSChecker.org | See global DNS for TXT |
✋ Common Issues You Might See
Problem | Likely Cause | Fix |
---|---|---|
Emails go to spam | Missing or bad SPF/DKIM/DMARC | Check & correct TXT records |
Gmail shows “via mailchannels.net” | SPF is OK but DKIM missing/failed | Ensure DKIM is active in Plesk |
Mail rejected by Microsoft or Gmail | DMARC policy too strict or misaligned | Use p=none temporarily if testing |
Customer moved email providers | Old TXT records still present | Update SPF/DKIM/DMARC per new host |
💡 What If the Customer Uses Gmail, Outlook, Zoho?
They’ll need new TXT records — usually:
- SPF like:
v=spf1 include:_spf.google.com ~all
(for Gmail) - DKIM: generated from the Gmail/Outlook admin console
- DMARC: same as before — optional, but recommended
📌 Agent Tip: Always ask:
“Where is your email hosted?”
“Are you using Webmail or a provider like Google or Microsoft?”
Then adjust records accordingly.
✅ Final Takeaways for Agents
- TXT records = email trust and authentication
- Plesk + Rebel email should use:
- SPF:
v=spf1 a mx include:relay.mailchannels.net -all
- DKIM: auto-enabled with
default._domainkey
- DMARC:
_dmarc
with a policy likep=quarantine
- SPF:
- Use tools like MXToolbox or DNSChecker to confirm outside
- Don’t mix records from multiple providers unless instructed