what's a valid domain name?

[Joseph S D Yao]

On Fri, Feb 04, 2011 at 11:26:08AM -0500, John Wobus wrote:
> So 10.14.22.11 is a legal hostname, right?
> 
> We had a recent experience where our DNS administration
> system allowed someone to insert in a CNAME record that
> resembled this:
> 
> www.example.com. CNAME 10.14.22.11.
> 
> A fascinating thing about this is that my computer/browser could
> take me to www.example.com just fine.


I'm guessing that someone stuck records like:

10.14.22.11	A	10.14.22.11

in your system at Cornell?  Otherwise, normally, the CNAME record above
would cause errors (i.e., if "10.14.22.11" were not a name, as well).

You can't check this with 'nslookup' - you need to use 'dig'.  [Nobody
need respond with the well-known merits and failings of 'nslookup'.]


--
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** Joe Yao				jsdy at tux.org - Joseph S. D. Yao
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