TL;DR
Yes, having two or more DNS MX records pointing to the same IP address is generally a single point of failure and offers no real availability benefit. It’s better to use multiple servers with different IPs for redundancy.
Understanding the Problem
MX (Mail Exchange) records tell email systems where to deliver emails for your domain. They also have a priority number – lower numbers mean higher preference. If two MX records point to the same IP, you’re not increasing resilience; you’re just repeating the same server in your DNS.
Solution: Fix Duplicate MX Records
- Check Your Current MX Records
- Use a tool like MXToolBox or the command line to see your existing records.
- From the command line (Linux/macOS):
dig yourdomain.com MX - Identify Duplicate IPs
- Look at the ‘IN A’ record associated with each IP address listed in your MX records. If multiple MX records resolve to the same IP, you have duplicates.
- Remove Redundant Records
- Log into your DNS provider’s control panel (e.g., Cloudflare, GoDaddy, Namecheap).
- Find the section for managing DNS records.
- Delete all but one of the MX records pointing to the duplicated IP address. Keep the record with the lowest priority number.
- Add Records Pointing to Different Servers (Recommended)
- For true redundancy, add MX records that point to different email servers/IP addresses. This means using a backup mail server in addition to your primary one.
- Example:
- MX Record 1: Priority 10, points to
mail1.example.com(IP address: 192.0.2.1) - MX Record 2: Priority 20, points to
mail2.example.com(IP address: 198.51.100.1)
- Test Your Changes
- After making changes, use MXToolBox or the command line again to verify that your MX records are correct and point to the intended servers.
dig yourdomain.com MX - Send a test email to your domain from an external account (e.g., Gmail, Outlook) to confirm delivery works as expected.
Why This Matters
If the single IP address hosting your duplicate MX records goes down, all email delivery fails. Multiple servers with different IPs provide a failover mechanism – if one server is unavailable, emails will be routed to another.