Talk:CNAME record

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DNAME[edit]

The description of DNAME is unfortunately completely wrong.

DNAME only redirects subdomains.

Moreover the standard does not currently allow a CNAME and DNAME to be defined for the same node. —Preceding unsigned comment added by 92.238.99.235 (talk) 20:37, 10 June 2010 (UTC)

The DNAME example suggests the principle stated above, when it says that an A-lookup for foo fails. That contradicts the assertion in the main paragraph, which says that a "DNAME maps a domain and it's subdomains". Change that to simple "subdomains", and it's accurate. I am about to make that change, after seeing the confirmation above. (I am not adding the part about CNAME and DNAME not allowed for the same node, although possibly I should.) 75.41.52.94 (talk) 17:48, 5 November 2010 (UTC)

The best use of DNAME that never was:

ip6.int.   IN   DNAME   ip6.arpa.

- 71.106.211.51 (talk) 02:44, 16 November 2011 (UTC)

CNAME wording nit, details section[edit]

Suggest changing the wording: "CNAME must have no other resource records of other types" to something like "a node with a CNAME record must have no other resource records". Current wording makes it sound as if the CNAME record itself could have a record, or as if a node could have more than one CNAME record, neither of which is the case, AFAIK. Chconnor (talk) 02:27, 14 November 2010 (UTC)

I agree; the sentence in confusing. As someone trying to learn DNS better, this sentence makes me ask "What does 'have' mean? ...reference? ...be used in?". And my wording nit: if "other" is really needed twice, change one to "different".
Would it be correct to say "An alias defined by a CNAME record should not be used in resource records of other types (SOA, NS, MX, A, etc)."? Pbyhistorian (talk) 18:45, 23 October 2011 (UTC)

Wording issue...[edit]

Suggest changing...

The canonical name itself must be defined by a record other than a CNAME or DNAME record.

To...

The canonical name itself must be defined by another record.

—Preceding unsigned comment added by 174.114.248.239 (talk) 20:28, 11 March 2011 (UTC)

It's a while since I've looked at this, but my recollection is that the other record cannot be a CNAME or DNAME, so doesn't that need to be mentioned? I take the point that in a big-picture sense, the proposed wording is correct and simpler (which is good), but perhaps needs the qualification. Johnuniq (talk) 22:43, 11 March 2011 (UTC)

Kmp Surya suman (talk) 10:55, 21 December 2016 (UTC)

obligation contradiction[edit]

The expression "The canonical name itself must be defined by a record other than..." is likely understood as forbidding using a CNAME record with a canonical name. If the subsequent clarification "CNAME records that point to other CNAME records ... are not an error" is correct, I suggest altering the first statement from "must be" to "is usually". — Preceding unsigned comment added by 83.251.187.111 (talk) 16:26, 11 May 2012 (UTC)

Conflicting A and CNAME records — precedence?[edit]

Consider the following DNS setup:

www.example.com.      IN      A       192.0.43.10
  *.example.com.      IN      CNAME   www.google.com
  • The first line signifies that www.example.com shall point to IP address 192.0.43.10, the IP address of the IANA example HTTP server.
  • The second line signifies that any subdomain in example.com, including the www subdomain, shall point to www.google.com.

What is considered the default behavior now? Shall a client (e.g. a web browser) go to the IANA example HTTP server or the www.google.com HTTP server? --Abdull (talk) 00:26, 19 July 2012 (UTC)

This is a good question. I can't believe this Talk page has not been visited by an expert in five years! David Spector (talk) 13:20, 24 October 2017 (UTC)
From RFC 1912 [ https://tools.ietf.org/html/rfc1912 ]:
2.4 CNAME records
A CNAME record is not allowed to coexist with any other data. In other words, if suzy.podunk.xx is an alias for sue.podunk.xx, you can't also have an MX record for suzy.podunk.edu, or an A record, or even a TXT record.
-Guy Macon (talk) 03:04, 25 October 2017 (UTC)

CNAMEs using identifiers as alias URIs[edit]

In the authoritative DNS zones for my websites, my hosting company has frequently used identifiers as alias URIs.

Here are some examples:

springtimesoftware.com. A 64.131.68.211
www CNAME springtimesoftware.com.
ftp CNAME springtimesoftware.com.

In a browser, the URL springtimesoftware.com. is directly translated to IP address 64.131.68.211, but the first CNAME record makes this also true for URL www.springtimesoftware.com. Using FTP, a hostname ftp.springtimesoftware.com will also be translated to 64.131.68.211.

So the record "www CNAME springtimesoftware.com." appears to be treated exactly like "www.springtimesoftware.com. CNAME springtimesoftware.com.".

This article (and other articles on the Web) fail to describe this case of using an identifier (such as www or ftp) as the alias name in a CNAME record.

Can anyone explain this omission? Am I missing something obvious? Should the article be edited? David Spector (talk) 13:19, 24 October 2017 (UTC)