Category: Before Enabling Filtering Services | Protocol: DNS
MX (Mail eXchange) records define which server(s) incoming emails should be routed to within your DNS zone. Modifying MX records is the key step to enable e-securemail filtering on your domain.
I — Understanding MX Records
An MX record consists of a priority (numeric value) and a target server. The lower the value, the higher the priority.
Example: if two MX records are configured:
| Server | Priority | Role |
|---|---|---|
| france.security-mail.net | 10 | Primary server (highest priority) |
| europe.security-mail.net | 20 | Backup server (used if the primary server does not respond) |
II — Situation Before the Change
Without filtering, your emails are delivered directly to your mail server without prior analysis. All messages — including spam and malware — reach your mailbox.
| Existing Server (example) | Priority | Role |
|---|---|---|
| mailgate.your-domain.com | 5 | Current primary server |
| smtp.isp.net | 40 | ISP backup relay |
III — New MX Configuration (with Filtering)
To enable e-securemail filtering, replace all your MX records with:
| Server | Priority | Role |
|---|---|---|
| france.security-mail.net | 10 | Primary filtering server |
| europe.security-mail.net | 20 | Backup server (redundancy) |
⚠️ Important: Remove all old MX records. If an old MX record remains with a priority lower than 10, it may allow spam to bypass the filtering system.
IV — Deployment Steps
Log in to your DNS zone management interface (registrar, DNS provider, ISP)
Remove all existing MX records
Add the two new MX records listed above
Save the changes and wait for DNS propagation
💡 Propagation Delay: DNS changes generally take anywhere from a few minutes to 24 hours to propagate across the Internet, depending on the configured TTL.
V — Verify the Configuration
From a terminal:
nslookup -type=mx your-domain.com
The output should display only:
your-domain.com MX preference = 10, mail exchanger = france.security-mail.net
your-domain.com MX preference = 20, mail exchanger = europe.security-mail.net
VI — Checkpoints
Lower number = higher priority (MX 10 > MX 20)
No old MX records should remain
Ask your ISP or DNS provider for a complete replacement if you do not have direct access
After propagation, send a test email to your domain and verify that it passes through the filtering system