Can CNAME update, bring website down?

Question

We updated CNAME on a production website, after updating it website showed "server's DNS address could not be found" message for about 8 mins. Could this be because of the change in CNAME?

score 1 · Answer 1 · answered Apr 19 '16 at 20:42

1

Did you change it as a delete/create or as a update? Delete/create could cause an outage. A straight update is safe and does not result in a not-found message.

answered Apr 19 '16 at 20:42

Jason Martin

5,193

score 1 · Accepted Answer · answered Apr 20 '16 at 06:16

From our discussion in the comments, it looks like you attempted to set an IP address target using a CNAME record. This record type is only intended to alias the host resources of one name to another, and the value will be interpreted as a name even if you input an IP address.

Input:

 $ORIGIN example.com.
 www     IN CNAME 203.0.113.0

Effective output with FQDNs:

 $ORIGIN example.com.
 www.example.com.     IN CNAME 203.0.113.0.example.com.

This mistake almost always results in NXDOMAIN (barring wildcard matching), as the target is very unlikely to exist.

score 0 · Answer 3 · answered Apr 19 '16 at 20:23

0

If you have added the CNAME records for your domain with the record name www or with a blank record name, your website may not be accessible until the DNS records are propagated.

answered Apr 19 '16 at 20:23

mohemmadAli

92

Can CNAME update, bring website down?

3 Answers3