nanog mailing list archives
Re: DNS hostnames with a duplicate CNAME and A record - which should be removed?
From: Tony Finch <dot () dotat at>
Date: Thu, 18 Oct 2012 09:56:56 +0100
Landon Stewart <lstewart () superb net> wrote:
The problem is that we have some zones that have records with the same hostname that have both a CNAME as well as an A record, MX record, SOA record and/or NS record. Is there an easy answer for what should be removed?
You can never have a CNAME record at a zone apex, because a zone apex has to have SOA and NS RRs and a CNAME can never coexist with other RRs. So those cases are simple. If the misconfigured CNAME is not at a zone apex then you have to decide whether the CNAME or the other records are correct - do you get the right result from the DNS when deleting one or the other? If it works either way then your decision mainly depends on how frequently the target address changes and if you need to make co-ordinated changes across many zones - if so then a CNAME tends to be preferable. But you probably have to have a workaround for A records at zone apexes in which case that tooling probably removes CNAMEs' advantage and you might as well use A records everywhere. Tony. -- f.anthony.n.finch <dot () dotat at> http://dotat.at/ Forties, Cromarty: East, veering southeast, 4 or 5, occasionally 6 at first. Rough, becoming slight or moderate. Showers, rain at first. Moderate or good, occasionally poor at first.
Current thread:
- DNS hostnames with a duplicate CNAME and A record - which should be removed? Landon Stewart (Oct 17)
- Re: DNS hostnames with a duplicate CNAME and A record - which should be removed? Andrew Sullivan (Oct 17)
- Re: DNS hostnames with a duplicate CNAME and A record - which should be removed? William Herrin (Oct 17)
- Re: DNS hostnames with a duplicate CNAME and A record - which should be removed? Tony Finch (Oct 18)
- Re: DNS hostnames with a duplicate CNAME and A record - which should be removed? jeff weisberg (Oct 18)
- Re: DNS hostnames with a duplicate CNAME and A record - which should be removed? Landon Stewart (Oct 18)
- Re: DNS hostnames with a duplicate CNAME and A record - which should be removed? Jimmy Hess (Oct 19)
- Re: DNS hostnames with a duplicate CNAME and A record - which should be removed? Masataka Ohta (Oct 19)