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You're not looking up the CNAME record using host -t, you're looking
up a record of a type CNAME. You can't reverse a lookup... this is
why the first lookup works, and the second fails. It's similar to
why you need both an A record and a PTR record to lookup a name and
the address.
So this isn't a MS DNS thing, it's just a DNS thing.
dpk
On Feb 19, 2008 7:49 AM, Eric Weston <[log in to unmask]> wrote:
> Anyone know how a Microsoft DNS server handles CNAME records? We have a
> MS DNS server here, and when I do DNS lookups using UNIX tools, such as
> nslookup, dig, host, and the Python socket module, I get expected
> results for simple host name queries and reverse queries, but I get null
> sets for alias (CNAME) queries. I did this query using host:
>
> "host -t CNAME xxxx.lib.msu.edu"
>
> on one of our servers that has multiple aliases, and it came back with
>
> "xxxx.lib.msu.edu has no CNAME record"
>
> When I did a query using one of the aliases
>
> "host yyyy.lib.msu.edu"
>
> it returned
>
> "yyyy.lib.msu.edu is an alias for xxxx.lib.msu.edu"
>
> So apparently host can recognize an alias, but when you query a host
> name or IP for CNAME records, it finds none. Which makes me wonder if a
> CNAME record on a Microsoft DNS server is different from a CNAME record
> on non-Microsoft DNS servers.
>
> Thoughts?
>
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