I had an issue today with our DNS server. The new DNS entries weren’t resolving. It was found that two CNAME entries in the DNS were pointing to different servers which screwed up the DNS. Here’s what I used to get the error in the DNS table:
Got a dump of the Zone data in a file. Then executed named-checkzone on the dump file to get the incorrect entry:
Login to your DNS server and execute the following command:
dig @localhost yourdomain.net axfr > tmp
Execute named-checkzone on the dump file to view results
named-checkzone yourdomain.net tmp
tmp:1366: ignoring out-of-zone data (some-site-without-domain) tmp:1419: ignoring out-of-zone data (some-test-site-without-domain) dns_master_load: tmp:6566: PROBLEM.yourdomain.net: multiple RRs of singleton type zone yourdomain.net/IN: loading from master file tmp failed: multiple RRs of singleton type zone yourdomain.net/IN: not loaded due to errors.
Sample data from tmp file
some-site-without-domain. 86400 IN CNAME web-server.yourdomain.net. problem.yourdomain.net. 86400 IN CNAME web-server.yourdomain.net. some-site.yourdomain.net. 86400 IN CNAME another-web-server.yourdomain.net. more-site.yourdomain.net. 86400 IN CNAME web-server-1.yourdomain.net. PROBLEM.yourdomain.net. 86400 IN CNAME web-server-2.yourdomain.net.