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DNS Troubleshooting FAQ

​​ Why do I have a dc-######### subdomain?

The dc-##### subdomain is added to overcome a conflict created when your SRV or MX record resolves to a domain configured to proxy to Cloudflare.

Therefore, Cloudflare will create a dc-##### DNS record that resolves to the origin IP address. The dc-##### record ensures that traffic for your MX or SRV record isn’t proxied (it directly resolves to your origin IP) while the Cloudflare proxy works for all other traffic.

For example, before using Cloudflare, suppose your DNS records for mail are as follows:

example.com MX example.com example.com A 192.0.2.1

After using Cloudflare and proxying the A record, Cloudflare will provide DNS responses with a Cloudflare IP (203.0.113.1 in the example below):

example.com MX example.com example.com A 203.0.113.1

Since proxying mail traffic to Cloudflare would break your mail services, Cloudflare detects this situation and creates a dc-##### record:

example.com MX dc-1234abcd.example.com dc-1234abcd.example.com A 192.0.2.1 example.com A 203.0.113.1

Removing the dc-###### record is only possible via one of these methods:

  • If no mail is received for the domain, delete the MX record.
  • If mail is received for the domain, update the MX record to resolve to a separate A record for a mail subdomain that isn’t proxied by Cloudflare:

example.com MX mail.example.com mail.example.com A 192.0.2.1 example.com A 203.0.113.1

​​ Why are DNS queries returning incorrect results?

Third-party tools can sometimes fail to return correct DNS results if a recursive DNS cache fails to refresh. In this circumstance, purge your public DNS cache via these methods:

​​ No A, AAAA or CNAME record found?

No A, AAAA or CNAME record found means the Cloudflare DNS app lacks proper records for DNS resolution.

Add the missing DNS records to your domain.

​​ Why have I received an email: Your Name Servers have Changed?

For domains where Cloudflare hosts the DNS, Cloudflare continuously checks whether the domain uses Cloudflare’s nameservers for DNS resolution. If Cloudflare’s nameservers are not used, the domain status is updated from Active to Moved in the Cloudflare Overview app and an email is sent to the customer.  Any domain Moved for more than 7 days is deleted unless the domain again becomes Active.

Steps to resolve the issue require updating the DNS at your domain registrar to utilize the Cloudflare nameservers:

  1. Follow steps 2 and 3 within our  domain troubleshooting article.
  2. Click Re-check Now in the Cloudflare UI Overview app.

​​ Why can’t I add certain TLDs via the DNS API?

The DNS API cannot be used for domains with .cf, .ga, .gq, .ml, or .tk TLDs. Use the Cloudflare Dashboard for managing such TLDs. Enterprise customer can  contact Cloudflare Support to remove this limitation.