How to Configure MX Records for a Cloud Spam Filter (Step-by-Step)

What Are MX Records?

An MX record — short for Mail Exchanger record — is a DNS entry that tells the internet where to deliver email for your domain. When someone sends a message to you@example.com, their mail server looks up the MX records for example.com and connects to whatever host is listed there.

To route inbound email through a cloud spam filter, you point your MX records at the filter's servers instead of your own mail server. Every message destined for your domain passes through the proxy first, gets scanned and scored, and the clean mail is forwarded on to your actual mail server. Your mail server never sees the junk.

The records you need to add are:

Priority  Host
10        mx1.spamkiller.online
20        mx2.spamkiller.online

What Does MX Priority Mean?

The priority number tells sending mail servers which host to try first. Lower numbers are higher priority. With priority 10 on mx1 and priority 20 on mx2, all mail goes to mx1 first. If that server is unreachable, the sending server automatically retries against mx2. This gives you redundancy without any configuration on your end — if one node is down for maintenance, email keeps flowing through the other.

You want two records for the same reason you want two exits in a building: failover. A single MX record means any outage on that host causes inbound mail to queue up at the sender and eventually bounce. Two records at different priorities eliminate that single point of failure.

GoDaddy

GoDaddy's DNS editor is found inside the Domains section of your account.

1. Sign in at godaddy.com and click your account name in the top right, then select My Products.
2. Find your domain and click the DNS button next to it.
3. Scroll down to the MX section. You will see your current MX records here.
4. Click Add New Record and select MX from the type dropdown.
5. For the first record, fill in:
   • Name: @ (the @ symbol represents the root domain)
   • Value: mx1.spamkiller.online
   • Priority: 10
   • TTL: 1 hour (or 3600 seconds)
6. Click Save, then click Add New Record again.
7. Add the second record with:
   • Name: @
   • Value: mx2.spamkiller.online
   • Priority: 20
   • TTL: 1 hour
8. Click Save.
9. Delete or update your old MX records once the new ones have propagated (see the Propagation section below).

Cloudflare

Cloudflare manages DNS through its dashboard under the DNS tab for your zone.

1. Sign in at dash.cloudflare.com and select the domain you want to configure.
2. Click DNS in the left sidebar, then Records.
3. Click the Add record button.
4. Set the type to MX.
5. For the first record:
   • Name: @
   • Mail server: mx1.spamkiller.online
   • Priority: 10
   • TTL: Auto (or set to 3600 if you prefer manual)
6. Click Save.
7. Click Add record again for the second:
   • Name: @
   • Mail server: mx2.spamkiller.online
   • Priority: 20
   • TTL: Auto
8. Click Save.
9. Remove your old MX records by clicking the Edit icon next to each and selecting Delete.

Cloudflare's DNS is among the fastest to propagate globally — changes often take effect within minutes rather than hours.

AWS Route 53

Route 53 uses hosted zones. Each domain has a hosted zone, and records live inside it.

1. Open the AWS Console and navigate to Route 53 under Services.
2. Click Hosted zones in the left panel and select your domain.
3. Click Create record.
4. Set the record type to MX.
5. Leave the Record name field blank (this sets the record on the root/apex of the domain).
6. In the Value field, enter both records on separate lines in Route 53's format — priority first, then hostname:

   10 mx1.spamkiller.online.
   20 mx2.spamkiller.online.

   Note the trailing dots — Route 53 requires them to indicate fully qualified domain names.

7. Set TTL to 300 seconds (5 minutes) initially so you can iterate quickly, then raise it to 3600 once things are confirmed working.
8. Click Create records.
9. Delete the old MX record set by selecting it and clicking Delete record.

Route 53 allows you to enter both MX records in a single record set, which is the standard approach. Each line in the value field is treated as a separate priority/host pair.

Namecheap

Namecheap calls its DNS editor the Advanced DNS panel, accessible from your domain list.

1. Sign in at namecheap.com and go to Domain List from the left sidebar.
2. Click Manage next to your domain.
3. Select the Advanced DNS tab.
4. Scroll down to the Mail Settings section. If you see a dropdown for mail provider, switch it to Custom MX.
5. Click Add New Record.
6. Set the type to MX Record and fill in:
   • Host: @
   • Value: mx1.spamkiller.online
   • Priority: 10
   • TTL: Automatic
7. Click the green checkmark to save, then click Add New Record again.
8. Add the second record:
   • Host: @
   • Value: mx2.spamkiller.online
   • Priority: 20
   • TTL: Automatic
9. Save the record. Remove any old MX entries by clicking the trash icon next to them.

Verifying the Change

Once you have saved the new records, you can check whether they have propagated using dig on Linux/macOS or nslookup on Windows.

Using dig (Linux / macOS)

dig MX yourdomain.com

Look for the ANSWER SECTION in the output. You should see something like:

yourdomain.com.  3600  IN  MX  10 mx1.spamkiller.online.
yourdomain.com.  3600  IN  MX  20 mx2.spamkiller.online.

To query a specific DNS server (useful for checking before full propagation):

dig MX yourdomain.com @8.8.8.8

Using nslookup (Windows)

nslookup -type=MX yourdomain.com

Expected output:

yourdomain.com  MX preference = 10, mail exchanger = mx1.spamkiller.online
yourdomain.com  MX preference = 20, mail exchanger = mx2.spamkiller.online

If you still see your old MX records, the change has not propagated to the DNS server you're querying yet. Try querying Google's DNS directly with nslookup -type=MX yourdomain.com 8.8.8.8.

DNS Propagation and TTL

DNS propagation is the process of your updated records spreading to DNS servers around the world. It is not instant. The time it takes depends primarily on the TTL (Time to Live) of your old records.

TTL is measured in seconds and tells DNS resolvers how long to cache a record before re-checking. If your old MX records had a TTL of 86400 (24 hours), resolvers that already cached them may not pick up the new records for up to 24 hours — even though your changes are saved at your registrar.

How to Speed Up Propagation

The best practice is to lower your TTL to 300 seconds (5 minutes) at least an hour before you make the change. Once resolvers refresh their cache with the low-TTL record, your subsequent change will propagate within minutes. After the migration is confirmed stable, raise the TTL back to 3600 or higher.

In practice, most of the internet has updated within 1–4 hours even with higher TTLs, because resolvers check frequently. Full global propagation can take up to 48 hours in rare cases.

What to Do During Propagation

During the propagation window, some mail servers will route to your old MX records and some will route to the new ones. This is normal and expected. Your old mail server should still be running and accepting mail during this period.

• Keep your old mail server accepting connections until propagation is complete.
• Do not shut down or block access to the upstream server the spam filter is configured to forward to.
• Monitor both the spam filter dashboard and your mail server logs for incoming messages.
• Use dig MX yourdomain.com @1.1.1.1 and @8.8.8.8 periodically to check whether major resolvers have updated.

Once dig consistently returns only your new MX records from multiple DNS servers, propagation is complete.

Confirming Email Is Flowing Through the Proxy

After propagation, the easiest way to confirm email is routing through Spam Killer is to look at the headers of a received message.

In most email clients you can view full headers through a menu option like View Source, Show Original, or View Raw Message. Look near the top of the headers for a Received: line that references the spam filter's hostname:

Received: from mx1.spamkiller.online (mx1.spamkiller.online [203.0.113.10])
        by mail.yourdomain.com with ESMTP id abc123
        for <you@yourdomain.com>;
        Mon, 10 Mar 2026 09:14:22 +0000

You should also see Spam Killer's scoring headers appended to the message:

X-Spam-Status: No, score=1.4
X-Spam-Score: 1.4
X-Spam-Bar: +

If these headers are present, email is flowing through the proxy as expected. If you see the old mail server's hostname in the Received: chain without any Spam Killer entry, the message arrived before propagation completed — or via a DNS resolver that has not yet updated. Give it another hour and test again.